Internal focusing zoom lens system
An internal focusing zoom lens comprises a first lens group of positive refracting power, a second lens group of negative refracting power, a third lens group of positive refracting power and a fourth lens group of positive refracting power disposed in the named order from the object side, in which at least the first lens group, the third lens group and the fourth lens group move toward an object along the optical axis during zooming from wide angle to telephoto such that an air gap increases between the first lens group and the second lens group, an air gap decreases between the second lens group and the third lens group and an air gap decreases between the third lens group and the fourth lens group, in which the second lens group moves toward the object along the optical axis during focusing, and which satisfies various conditions.
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1. Field of the Invention
The present invention relates to a zoom lens, and more particularly to an internal focusing zoom lens.
2. Related Background Art
There are recently studied various focusing methods for enabling the size reduction of focusing lens group in addition to the size reduction and the pursuit of high performance of zoom lens with spread of autofocus of camera lens. However, if a compact wide ratio zoom lens includes a compact focusing lens group in simple focusing method, a change in aberration upon focusing is great, and performance in short distance photographing is always sacrificed. On the other hand, if the focusing lens group is relatively compact with high performance in short distance photographing, the focusing method is complex in contrast.
For example, Japanese Laid-open Patent Application No. 3-228008 employs the zoom method with four lens groups, e.g., positive, negative, positive and negative lens groups, in which upon zooming from wide angle to telephoto an air gap increases between first lens group and second lens group, an air gap decreases between second lens group and third lens group, and an air gap increases between third lens group and fourth lens group. Thus, the introduction of focusing method using the second lens group did not result in achievement of sufficient size reduction and correction of aberration change.
Further, Japanese Laid-open Patent Application No. 4-140704 tried to achieve the size reduction by employing the zoom method with four lens groups, e.g., positive, negative, positive and positive lens groups, in which all the lens groups move toward an object upon zooming from wide angle to telephoto such that an air gap increases between first lens group and second lens group, an air gap decreases between second lens group and third lens group, and an air gap decreases between third lens group and fourth lens group. However, it failed to study the optimum power arrangement for the respective lens groups, which resulted in a great change of total length upon zooming from wide angle to telephoto. Thus, the application failed to achieve an optical system compact in size and less sensitive to eccentricity.
SUMMARY OF THE INVENTIONIt is, therefore, an object of the present invention to provide an internal focusing zoom lens, which is compact in size and wide in variable power, in which a focusing lens group is very small and a focusing method is very simple, and which is always excellent in imaging property in the entire photographic range from infinity to the closest distance.
The present invention is based on the study of optimum power arrangement, which found an internal zoom lens having a compact zoom lens system in total and a very small work (weight.times.displacement amount) for focusing by focusing lens group. Specifically, as shown in FIG. 1, an internal focusing zoom lens system of the present invention comprises in order from the object side a first lens group G1 of positive refracting power, a second lens group G2 of negative refracting power, a third lens group G3 of positive refracting power, and a fourth lens group G4 of positive refracting power, in which upon zooming from wide angle to telephoto at least the first lens group G1, the third lens group G3, and the fourth lens group G4 move toward an object such that an air gap increases between the first lens group G1 and the second lens Group G2, an air gap decreases between the second lens Group G2 and the third lens group G3, and an air gap decreases between the third lens group G3 and the fourth lens group G4, and in which upon focusing the second lens group G2 moves toward the object and the following conditions are satisfied;
3.0<f.sub.1 /-f.sub.2 <6.0 (1);
2.2<-f.sub.2 /f.sub.w.sup.1/2 <3.3 (2);
15.0<f.sub.1.sup.2 .multidot..beta..sub.2w.sup.2 /(1-.beta..sub.2w.sup.2).multidot.f.sub.w <35.0 (3);
where
f.sub.1 : a focal length of the first lens group G1;
f.sub.2 : a focal length of the second lens group G2;
.beta..sub.2w : a lateral magnification of the second lens group G2 at the wide angle end to infinity;
f.sub.w : a focal length of the overall system at wide angle end.
In the present invention, a wide ratio standard zoom lens employs the zoom system with four lens groups, e.g., positive, negative, positive and positive lens groups, compact in size and relatively simple in structure, in which upon focusing the compact and light second lens group is moved toward the object along the optical axis to effect focusing onto the object in short distance. It is generally better in order to suppress the aberration change upon the object distance that the lens groups are respectively corrected in aberration and that the focusing lens group has a small displacement amount for focusing and a small positional change of rays passing therethrough during movement of the focusing lens group. The present invention succeeded to minimize the aberration change upon the object distance with suppressed displacement for focusing of the second lens group, which is the focusing lens group, based on the study on the optimum power arrangement and shapes of the lens groups. Therefore, compact and high-performance internal focusing zoom lenses may be attained irrespective of states of zooming or focusing.
The conditions in the present invention will be described in the following.
Condition (1) shows the optimum ratio of focal lengths between the first lens group G1 and the second lens group G2 in zoom lens according to the present invention. If a zoom lens is arranged as in the present invention such that the first lens group G1 moves along the optical axis upon zooming from wide angle to telephoto, a longer focal length f.sub.1 is more advantageous for aberration correction, but a change of total length increases upon zooming. Regarding the lateral magnification .beta..sub.2 of the second lens group G2 to an object at infinity, the lateral magnification .beta..sub.2 (more strictly, an absolute value thereof) decreases as the refracting power of first lens group G1 becomes lower (as the focal length f.sub.1 becomes longer) or as the refracting power of second lens group G2 becomes higher. Let a feed amount for focusing by the second lens group be .DELTA.X, a photographic distance be R, and the total length of lens system (a distance from the tip end of lens system to the film plane) be TL. Then, the feed amount .DELTA.X may be generally expressed by the following approximation.
.DELTA.X=f.sub.1.sup.2 /(1/.beta..sub.2.sup.2 -1).multidot.(R-TL-f.sub.1) (a)
From the above equation, the approximation, R-TL-f.sub.1 .congruent.R, holds with sufficiently large R. With fixed photographic distance R, the feed amount .DELTA.X is substantially proportional only to f.sub.1.sup.2 /(1/.beta..sub.2.sup.2 -1). Accordingly, the following equation is defined as Equation (b).
Y=f.sub.1.sup.2 /(1/.beta..sub.2.sup.2 -1) (b)
As seen from the above equation, the feed amount .DELTA.X for focusing may be made smaller as .beta..sub.2.sup.2 becomes smaller as .beta..sub.2.sup.2 .fwdarw.0. The magnification .beta..sub.2 is a function of f.sub.1 as expressed by Equation (c) with a distance D.sub.1 between principal points of the first lens group G1 and the second lens group G2.
.beta..sub.2 =f.sub.2 /(f.sub.1 +f.sub.2 -D.sub.1) (c)
Using Equation (c), Equation (b) may be changed as follows.
Y=f.sub.1.sub.2 f.sub.2.sup.2 /{(f.sub.1 +f.sub.2 -D.sub.1).sup.2 -f.sub.2.sup.2 } (d)
Differentiating Equation (d) with respect to f.sub.1 and changing its form, Equation (e) is obtained.
dY/df.sub.1 =2f.sub.1 f.sub.2.sup.2 {(f.sub.1 +f.sub.2 -D.sub.1)(f.sub.2 -D.sub.1)-f.sub.2.sup.2 }/{(f.sub.1 +f.sub.2 -D.sub.1).sup.2 -f.sub.2.sup.2 }.sup.2 (e)
Since f.sub.1 >0 and D.sub.1 >0,
{(f.sub.1 +f.sub.2 -D.sub.1).sup.2 -f.sub.2.sup.2 }.sup.2 >0 (f);
f.sub.1 f.sub.2.sup.2 >0 (g).
In four lens group zoom systems with positive, negative, positive and positive lens groups as in the present invention, the condition, -1<.beta..sub.2 <0, must be satisfied in order to enable the focusing by the second lens group in the entire zooming range from wide angle to telephoto. Then, the following condition holds from Equation (c), considering f.sub.2 <0.
(f.sub.1 +f.sub.2 -D.sub.1)>0
Further, since D.sub.1 >0, (f.sub.2 -D.sub.1)<0. Then,
(f.sub.1 +f.sub.2 -D.sub.1)(f.sub.2 -D.sub.1)<0.
Accordingly, Equation (h) holds.
(f.sub.1 +f.sub.2 -D.sub.1)(f.sub.2 -D.sub.1)-f.sub.2.sup.2 <0 (h)
From Equations (f), (g) and (h), Equation (e) is always negative, that is, dY/df.sub.1 <0. In other words, Equation (d) is a monotone decreasing function with respect to f.sub.1. It is thus seen from the above discussion that the feed amount .DELTA.X for focusing by the second lens group decreases as f.sub.1 increases. In summary, .DELTA.X decreases as the value of f.sub.1 increases or as the absolute value of f.sub.2 decreases. Accordingly, Condition (1) can be said as a conditional equation for defining the feed amount .DELTA.X for focusing. In other words, Condition (1) allows a zoom lens to assure the high performance at any photographic distance between the infinity and the shotest photographic distance while keeping the optical system compact. Below the lower limit of Condition (1), the feed amount .DELTA.X of second lens group for focusing becomes greater, which makes it difficult to suppress the aberration change upon the object distance within a limited range. Above the upper limit of Condition (1), the feed amount .DELTA.X for focusing can be kept small, but the change of total length upon zooming becomes greater, especially if the refracting power of first lens group G1 is low, which is likely to show the eccentricity in respect of mechanical design. On the contrary, if the refracting power of second lens group G2 is high, the aberration correction becomes difficult.
Condition (2) is a conditional equation for realizing a high-performance zoom lens while keeping the optical system compact. Below the lower limit of Condition (2), the refracting power of second lens group G2 becomes higher, which makes the aberration correction difficult. Above the upper limit of Condition (2), the refracting power of first lens group G1 must be lowered to satisfy Condition (1), which increases the change of total length upon zooming. This makes it impossible to realize a compact optical system less sensitive to eccentricity.
Condition (3) is for defining the feed amount .DELTA.X for focusing by the second lens group especially at wide angle end, as seen from the expression of Equation (b). Below the lower limit of Condition (3), the feed amount .DELTA.X at wide angle end can be made very small, but a power ratio between the first lens group G1 and the second lens group G2 becomes greater, which makes the aberration correction difficult and increases the size of entire lens system. Above the upper limit of Condition (3), the feed amount .DELTA.X at wide angle end becomes greater, which makes it difficult to suppress the aberration change upon object distance. Further, if a zoom lens system has a large zoom ratio, focusing becomes impossible at telephoto end.
In addition, the following condition should be preferably satisfied in order to achieve further size reduction and superior performance in the above arrangement.
0.8<f.sub.4 /f.sub.3 <3.0 (4)
In Equation (4),
f.sub.3 : a focal length of the third lens group G3;
f.sub.4 : a focal length of the fourth lens group G4.
Condition (4) shows the optimum ratio of focal lengths between the third lens group G3 and the fourth lens group G4 in zoom lens according to the present invention, specifically which greatly concerns the size of entire lens system and the aberration change correction upon zooming. In the range satisfying Condition (4), a zoom lens according to the present invention is so arranged that the third lens group G3 and the fourth lens group G4 are nearly afocal to an object at infinity on optical axis in the zooming of from wide angle to telephoto. Thus, changing the gap between them depending upon the condition of zooming can produce the effect of so-called floating, achieving a high-performance zoom lens less in aberration change upon zooming. Below the lower limit of condition (4), the total length of lens system becomes greater, and the nearly afocal arrangement of the third lens group G3 and the fourth lens group G4 is destroyed to make the reduction of aberration change upon zooming difficult. Above the upper limit of Condition (4), the nearly afocal arrangement is broken and the back focus is decreased, which makes impossible to construct a zoom lens as one for single-lens reflex camera. The effect of the present invention will be further enhanced if the lower limit is 1.0 and the upper limit is 2.0 in Condition (4).
If a zoom lens system is arranged to carry out focusing with second lens group, as in the present invention, the feed amount for focusing generally changes depending upon zooming. Then, a zoom lens system needing the so-called manual focus requires a special structure for enabling it. The cam structure on lens barrel for determining zooming and focusing functions of zoom lens System according to the present invention is preferably constructed as proposed in Japanese Patent Application No. 3-304887 filed by the same assignee as the present invention. In more detail, the zoom lens system according to the present invention is so arranged that if a certain movement locus for zooming is expressed with a variable of rotation angle of rotational barrel for defining a movement amount along the optical axis of the lens groups, a movement locus of the second lens group, which is the focusing lens group, is formed by a combination of a cam for focusing with a compensating cam for zooming, and a movement locus of each of the first lens group, the third lens group, and the fourth lens group, which are the movable non-focusing lens groups taking no part in focusing, is formed by a combination of the compensating cam for zooming with each cam for zooming for each lens group. As detailed in the aforementioned Japanese Patent Application No. 3-304887, the very simple arrangement of the double structure (the fixed barrel and the cam barrel) employing the cam structure can realize the manual focus of internal focusing zoom lens with second lens group which changes the feed amount for focusing. Specifically, the focus cam of the second lens group is shaped to assure a certain feed amount for focusing to a state of zooming at the same rotation angle for a specific photographic distance. Further, the compensating cam for zooming is so shaped that the combination thereof with the focus cam provides a movement locus of the second lens group upon zooming. The second lens group moves on the focus cam upon focusing, so that the second lens group moves by a desired feed amount along the optical axis to effect focusing. During zooming, the second lens group moves on the focus cam with rotation of the rotation barrel while combined with the rotational movement of the compensating cam for zoooming, so that the second lens group moves by a desired amount along the optical axis to effect zooming. Each zoom cam for movable first lens group, third lens group, or fourth lens group taking no part in focusing is so shaped that a combination thereof with the compensating cam for zooming provides a movement locus upon zooming of each lens group. During zooming, each lens group moves on each zoom cam with rotation of the rotation barrel, while combined with rotational movement of the compensating cam for zooming, so that each lens group moves by a desired amount along the optical axis to effect zooming.
BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a constitutional drawing to show the lens structure of zoom lens in Example 1 according to the present invention together with drawings to show movement loci for zooming of respective lens groups and with drawings to show shapes of cam for focusing, cams for zooming and compensating cam for zooming to define zooming and focusing;
FIG. 2 is an explanatory drawing for determining a cam for focusing in the zoom lens in Example 1 according to the present invention;
FIG. 3 is a constitutional drawing to show the lens structure of zoom lens in Example 2 according to the present invention together with drawings to show movement loci for zooming of respective lens groups and with drawings to show shapes of cam for focusing, cams for zooming and compensating cam for zooming to define zooming and focusing;
FIG. 4 is a constitutional drawing to show the lens structure of zoom lens in Example 3 according to the present invention together with drawings to show movement loci for zooming of respective lens groups and with drawings to show shapes of cam for focusing, cams for zooming and compensating cam for zooming to define zooming and focusing; and
FIG. 5 is a constitutional drawing to show the lens structure of zoom lens in Example 4 according to the present invention together with drawings to show movement loci for zooming of respective lens groups and with drawings to show shapes of cam for focusing, cams for zooming and compensating cam for zooming to define zooming and focusing.
DESCRIPTION OF THE PREFERRED EMBODIMENTSExamples of the present invention will be described in detail in the following.
EXAMPLE 1In Example 1, a zoom lens is composed in the order named from the object side, as shown in FIG. 1, of a first lens group G1 of positive refracting power, a second lens group G3 of negative refracting power, a third lens group G3 of positive refracting power, and a fourth lens group G4 of positive refracting power, in which all the lens groups move toward an object along the optical axis during zooming from wide angle to telephoto such that an air gap increases between the first lens group G1 and the second lens group G2, an air gap decreases between the second lens group G2 and the third lens group G3, and an air gap decreases between the third lens group G3 and the fourth lens group G4 and in which the second lens group G2 moves toward the object along the optical axis during focusing.
The construction of each lens group is as follows. The first lens group G1 of positive refracting power is composed of a negative meniscus lens L.sub.1 with convex plane on the object side, a double convex lens L.sub.2 bonded thereto, and a positive meniscus lens L.sub.3 with convex plane on the object side. The second lens group G3 of negative refracting power is composed of a negative meniscus lens L.sub.4 with larger curvature plane on the image side, a double concave negative lens L.sub.5, a positive meniscus lens L.sub.6 bonded thereto, and a positive meniscus lens L.sub.7 with convex plane on the object side. The third lens group G3 of positive refracting power is composed of a double convex positive lens L.sub.8, a double convex positive lens L.sub.9, and a negative lens L.sub.10 bonded thereto. The fourth lens group G4 of positive refracting power is composed of a positive lens L.sub.11, a double convex positive lens L.sub.12, and a negative meniscus lens L.sub.13 with larger curvature plane on the object side.
An aperture stop S is provided on the object side of the third lens group G3 as incorporated with the third lens group G3.
Table 1 shows specifications of the zoom lens in Example 1. In the table of specifications in Example 1, f represents a focal length (mm) and FN an F-number. In Table 1, r represents a radius of curvature of each lens plane (mm), d an interplanar gap between lenses (mm), n and .nu. an index of refraction and an Abbe's number of each lens. Accompanying numerals to the characters represent orders counted from the objective side. The middle portion of Table 1 shows values of coefficients defining the shape of an aspherical surface formed on the lens plane r.sub.6 on the object side in second lens group G2.
The aspherical surface is expressed by the following aspherical equation, if a height to the optical axis is h, a distance of a vertex of aspherical surface at h to the tangent plane is x, a conical constant is k, aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order are A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10, respectively, and a paraxial radius of curvature is r. ##EQU1##
In the middle portion of the specifications of lens system in Table 1, there are described in order from the left, values of the conical constant k, and the aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order, A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10. E.sub.-n means 10.sup.-n in the values of aspherical coefficients.
The lower portion in Table 1 shows gaps between lens groups and feed amounts for focusing for each photographic distance of infinity and 850.0 mm at three zooming positions (f=36.0, 60.0, and 103.0 mm) between wide angle end and telephoto end.
The bottom portion shows focal lengths of the lens groups, a lateral magnification of the second lens Group G2 at the wide angle end to infinity, and values corresponding to the conditions of the present invention.
The top portion of FIG. 1 is a drawing to show the lens construction of Example 1 according to the present invention, and the middle portion of FIG. 1 shows movement loci (g.sub.1, g.sub.2, g.sub.3, g.sub.4) of the lens groups during zooming with variable of rotation angle of the rotation barrel. Table 2 shows numerical values defining the movement loci. In Table 2, the left end column shows rotation angles .theta. (ANGLE) of rotation barrel, the right end column focal lengths (F), and four columns between the two end columns movement amounts of the lens groups along the optical axis.
As shown in the table, a rotation angle .theta. for zooming from the wide angle end to the telephoto end is set to 55.degree. in this example.
The bottom portion of FIG. 1 shows cam shapes actually formed on the rotation barrel of zoom lens according to the present invention. In FIG. 1, g.sub.2F denotes the focus cam for second lens group which is the focusing lens group, g.sub.1Z, g.sub.3Z and g.sub.4Z the zoom cams for first lens group, third lens group and fourth lens group, and g.sub.H the compensating zoom cam common to all the lens groups.
During actual zooming the movement locus g.sub.2 of second lens group which is the focusing lens group is formed by a combination of the focus cam g.sub.2F with the compensating zoom cam g.sub.H. Also, the moving loci g.sub.1, g.sub.3 and g.sub.4 of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam g.sub.H.
Table 3 shows numerical values defining the cam locus of the focus cam g.sub.2F. In Table 3, the left end column and the fourth column show rotation angles .theta. (ANGLE) of the rotation barrel, the second column and the fifth column movement amounts of the second lens group along the optical axis, and the third column and the right end column focal lengths (F). In the table, the rotation angle .theta. of rotation barrel of the focus cam g.sub.2F is set to 110.degree., which is a double of the rotation angle 55.degree. for zooming. This is because the rotation angle for focusing is set to 55.degree., which is the same rotation angle as that for zooming. Thus, the rotation angle .theta. of rotation barrel of the focus cam g.sub.2F is 110.degree. after the rotation angles for zooming and for focusing are combined with each other.
Next described with FIG. 2 is how to determine the focus cam. Since the rotation angle for focusing is set to 55.degree. which is identical to the rotation angle for zooming, the shape of focus cam g.sub.2F is specifically a combination of the focus cam trace defining the feed amount for focusing at wide angle end shown in Table 1 with the focus cam trace defining the feed amount for focusing at telephoto end. Suppose in FIG. 2 the feed amount for focusing is .DELTA.X.sub.f=36. R=850 at wide angle end and .DELTA.X.sub.f=103. R=850 at the telephoto end, respectively. If coordinates for wide angle end infinity are (X; .theta.)=(0; 0) and if coordinates for wide angle end photographic distance R=850.0 mm are (X; .theta.)=(.DELTA.X.sub.f=36. R=850 ; 55)=(1.036; 55), coordinates for telephoto end infinity are (X; .theta.)=(1.036; 55) and coordinates for telephoto end photographic distance R=850.0 mm are (X; .theta.)=(.DELTA.X.sub.f=36. R=850 +.DELTA.X.sub.f=103. R=850 ; 110)=(5.113; 110). In FIG. 2, R=un means that the photographic distance is infinity (unendlich). Further, the shape of focus cam g.sub.2F except for the above three points is determined as shown in Table 3 by utilizing the optimization method to obtain a feed amount for focusing necessary for arbitrary zooming state and photographic distance (for example, f=60.0 mm and R=850.0 mm).
Table 4 shows numerical values defining the cam loci of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group G1, third lens group G3 and fourth lens group G4. In Table 4, the left end column shows rotation angles .theta. (ANGLE) of the rotation barrel, the right end column focal lengths (F), and three columns between the two end columns movement amounts of the lens groups along the optical axis. The rotation angle .theta. for zooming from the wide angle end to the telephoto end is set to 55.degree. identical to that in Table 2.
Table 5 shows numerical values defining the cam locus of the compensating zoom cam g.sub.H common to all the lens groups. In Table 5, the left end column shows rotation angles .theta. (ANGLE) of the rotation barrel, the second column movement amounts of all the lens groups along the optical axis, and the right end column focal lengths (F).
As described above, during actual zooming, the movement locus g.sub.2 of the second lens group which is the focusing lens group is formed by a combination of the focus cam g.sub.2F with the compensating zoom cam g.sub.H, and the movement loci g.sub.1, g.sub.3 and g.sub.4 of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam g.sub.H. Therefore, if the movement amounts along the optical axis in Table 3 and Table 4 are added to the movement amounts along the optical axis in Table 5 in correspondence with each other, the sums should correspond to the movement amounts along the optical axis in Table 2.
Since the shape of focus cam is nonlinear to obtain a feed amount for focusing necessary for arbitrary magnification state and photographic distance, the shape of the compensating zoom cam, the shapes of the zoom cams for the respective lens groups, and the movement loci of the lens groups formed by combinations thereof all are also nonlinear as shown in FIG. 1.
Further, the barrel structure as described above can realize the manual focus of internal focusing zoom lens by the second lens group which changes the feed amount for focusing in the very simple arrangement of double structure (fixed barrel and cam barrel).
TABLE 1
__________________________________________________________________________
f =0 36.0-103.0 FN = 3.6-4.6
__________________________________________________________________________
r1 = 113.125
d1 = 1.500
n1 = 1.86074
.nu.1 = 23.0
L1
r2 = 58.096
d2 = 8.000
n2 = 1.51860
.nu.2 = 70.1
L2
r3 = -132.377
d3 = .100
r4 = 33.865
d4 = 3.800
n3 = 1.65160
.nu.3 = 58.5
L3
r5 = 57.386
d5 = 2.285
r6 = 52.180
d6 = 1.500
n4 = 1.67025
.nu.4 = 57.6
L4
r7 = 12.729
d7 = 5.100
r8 = -25.386
d8 = 1.100
n5 = 1.74810
.nu.5 = 52.3
L5
r9 = 33.461
d9 = 2.300
n6 = 1.86074
.nu.6 = 23.0
L6
r10 = 164.298
d10 = .100
r11 = 26.737
d11 = 1.900
n7 = 1.80458
.nu.7 = 25.5
L7
r12 = 48.903
d12 = 14.399
r13 = .000 d13 = 1.000
r14 = 48.706
d14 = 3.500
n8 = 1.51860
.nu.8 = 70.1
L8
r15 = -40.457
d15 = .100
r16 = 20.794
d16 = 6.200
n9 = 1.50137
.nu.9 = 56.5
L9
r17 = -21.868
d17 = 3.000
n10 = 1.80384
.nu.10 = 33.9
L10
r18 = 64.235
d18 = 5.600
r19 = .000 d19 = 3.028
r20 = -2358.593
d20 = 4.500
n11 = 1.65844
.nu.11 = 50.8
L11
r21 = =23.264
d21 = .100
r22 = 78.078
d22 = 3.300
n12 = 1.62280
.nu.12 = 57.0
L12
r23 = -53.919
d23 = 2.400
r24 = -19.264
d24 = 1.200
n13 = 1.79631
.nu.13 = 40.9
L13
r25 = -205.722
d25 = 41.122
r6 = .1000E + 01
.0000
-.3439E - 05
-.6965E - 07
.4212E - 09
-.1669E - 11
__________________________________________________________________________
pos (1)
pos (2)
pos (3)
pos (4)
pos (5)
pos (6)
__________________________________________________________________________
f&b 36.000
60.000
103.000
-.045 -.071
-.106
d0 .000 .000 .000 732.865
720.108
708.079
d5 2.285
13.128
23.354
1.249 11.258
19.276
d12 14.399
8.209 2.011
15.435 10.079
6.088
d19 3.028
1.779 1.119
3.028 1.779
1.119
d25 41.122
50.475
59.138
41.122 50.475
59.138
__________________________________________________________________________
F (1) (2) (3) (4) R (mm)
__________________________________________________________________________
1 36.0000
.0000 1.0357
.0000 .0000
850.00
2 60.0000
.0000 1.8702
.0000 .0000
850.00
3 103.0000
.0000 4.0775
.0000 .0000
850.00
__________________________________________________________________________
f1 = 71.353
f2 = 16.808
f3 = 37.322
f4 = 61.710
B = -.377
__________________________________________________________________________
(1) 4.25
(2) 2.80
(3) 23.43
(4) 1.65
TABLE 2
______________________________________
ANGLE (1) (2) (3) (4) F
______________________________________
.0000 .0000 .0000 .0000 .0000 36.0000
1.0000 .7295 .1094 .5119 .5693 37.0819
2.0000 1.4523 .2179 1.0118 1.1327 38.1840
3.0000 2.1684 .3253 1.5001 1.6893 39.3058
4.0000 2.8775 .4316 1.9771 2.2383 40.4470
5.0000 3.5795 .5369 2.4430 2.7789 41.6070
6.0000 4.2742 .6411 2.8980 3.3105 42.7853
7.0000 4.9613 .7442 3.3426 3.8322 43.9811
8.0000 5.6407 .8461 3.7769 4.3435 45.1939
9.0000 6.3121 .9468 4.2012 4.8438 46.4229
10.0000
6.9756 1.0463 4.6158 5.3325 47.6674
11.0000
7.6308 1.1446 5.0211 5.8091 48.9265
12.0000
8.2776 1.2416 5.4172 6.2732 50.1995
13.0000
8.9152 1.3373 5.8043 6.7243 51.4845
14.0000
9.5410 1.4311 6.1815 7.1615 52.7770
15.0000
10.1528 1.5229 6.5484 7.5845 54.0727
16.0000
10.7486 1.6123 6.9046 7.9930 55.3675
17.0000
11.3271 1.6991 7.2499 8.3870 56.6577
18.0000
11.8872 1.7831 7.5839 8.7664 57.9397
19.0000
12.4278 1.8642 7.9067 9.1315 59.2103
20.0000
12.9477 1.9422 8.2177 9.4819 60.4646
21.0000
13.4469 2.0170 8.5173 9.8184 61.7009
22.0000
13.9278 2.0892 8.8071 10.1430
62.9232
23.0000
14.3928 2.1589 9.0887 10.4581
64.1364
24.0000
14.8439 2.2266 9.3636 10.7652
65.3446
25.0000
15.2830 2.2925 9.6328 11.0661
66.5518
26.0000
15.7116 2.3567 9.8976 11.3620
67.7617
27.0000
16.1313 2.4197 10.1588
11.6543
68.9781
28.0000
16.5434 2.4815 10.4175
11.9441
70.2048
29.0000
16.9490 2.5424 10.6742
12.2323
71.4449
30.0000
17.3475 2.6021 10.9286
12.5180
72.6952
31.0000
17.7381 2.6607 11.1799
12.8003
73.9525
32.0000
18.1202 2.7180 11.4278
13.0783
75.2136
33.0000
18.4934 2.7740 11.6716
13.3514
76.4752
34.0000
18.8572 2.8286 11.9111
13.6188
77.7345
35.0000
19.2114 2.8817 12.1460
13.8802
78.9889
36.0000
19.5562 2.9334 12.3763
14.1354
80.2373
37.0000
19.8922 2.9838 12.6022
14.3846
81.4799
38.0000
20.2197 3.0330 12.8239
14.6278
82.7171
39.0000
20.5392 3.0809 13.0417
14.8653
83.9489
40.0000
20.8512 3.1277 13.2557
15.0971
85.1755
41.0000
21.1560 3.1734 13.4663
15.3236
86.3977
42.0000
21.4543 3.2181 13.6737
15.5451
87.6166
43.0000
21.7462 3.2619 13.8781
15.7618
88.8323
44.0000
22.0319 3.3048 14.0795
15.9738
90.0442
45.0000
22.3114 3.3467 14.2779
16.1812
91.2522
46.0000
22.5849 3.3877 14.4736
16.3841
92.4560
47.0000
22.8527 3.4279 14.6665
16.5827
93.6556
48.0000
23.1147 3.4572 14.8566
16.7769
94.8505
49.0000
23.3711 3.5057 15.0442
16.9671
96.0408
50.0000
23.6222 3.5433 15.2291
17.1532
97.2261
51.0000
23.8679 3.5802 15.4116
17.3353
98.4063
52.0000
24.1080 3.6162 15.5911
17.5132
99.5788
53.0000
24.3416 3.6512 15.7672
17.6864
100.7386
54.0000
24.5679 3.6852 15.9391
17.8541
101.8806
55.0000
24.7863 3.7180 15.1062
18.0160
103.0000
______________________________________
TABLE 3
______________________________________
ANGLE (2) F ANGLE (2) F
______________________________________
.0000 .0000 36.0000
1.0000 .0083 37.0819 56.0000 1.0749 .0000
2.0000 .0165 38.1840 57.0000 1.1153 .0000
3.0000 .0249 39.3058 58.0000 1.1569 .0000
4.0000 .0332 40.4470 59.0000 1.1997 .0000
5.0000 .0416 41.6070 60.0000 1.2438 .0000
6.0000 .0501 42.7853 61.0000 1.2892 .0000
7.0000 .0586 43.9811 62.0000 1.3359 .0000
8.0000 .0673 45.1939 63.0000 1.3841 .0000
9.0000 .0760 46.4229 64.0000 1.4338 .0000
10.0000
.0849 47.6674 65.0000 1.4850 .0000
11.0000
.0939 48.9265 66.0000 1.5378 .0000
12.0000
.1030 50.1995 67.0000 1.5921 .0000
13.0000
.1123 51.4845 68.0000 1.6482 .0000
14.0000
.1218 52.7770 69.0000 1.7057 .0000
15.0000
.1317 54.0727 70.0000 1.7647 .0000
16.0000
.1418 55.3675 71.0000 1.8250 .0000
17.0000
.1524 56.6577 72.0000 1.8864 .0000
18.0000
.1634 57.9397 73.0000 1.9489 .0000
19.0000
.1749 59.2103 74.0000 2.0123 .0000
20.0000
.1871 60.4646 75.0000 2.0766 .0000
21.0000
.2000 61.7009 76.0000 2.1417 .0000
22.0000
.2137 62.9232 77.0000 2.2076 .0000
23.0000
.2281 64.1364 78.0000 2.2746 .0000
24.0000
.2431 65.3446 79.0000 2.3426 .0000
25.0000
.2588 66.5518 80.0000 2.4119 .0000
26.0000
.2751 67.7617 81.0000 2.4825 .0000
27.0000
.2919 68.9781 82.0000 2.5545 .0000
28.0000
.3092 70.2048 83.0000 2.6280 .0000
29.0000
.3269 71.4449 84.0000 2.7031 .0000
30.0000
.3450 72.6952 85.0000 2.7798 .0000
31.0000
.3636 73.9525 86.0000 2.8578 .0000
32.0000
.3828 75.2136 87.0000 2.9372 .0000
33.0000
.4025 76.4752 88.0000 3.0179 .0000
34.0000
.4229 77.7345 89.0000 3.0999 .0000
35.0000
.4440 78.9889 90.0000 3.1830 .0000
36.0000
.4658 80.2373 91.0000 3.2672 .0000
37.0000
.4883 81.4799 92.0000 3.3526 .0000
38.0000
.5116 82.7171 93.0000 3.4393 .0000
39.0000
.5357 85.9489 94.0000 3.5272 .0000
40.0000
.5605 85.1755 95.0000 3.6163 .0000
41.0000
.5862 86.3977 96.0000 3.7068 .0000
42.0000
.6126 87.6166 97.0000 3.7987 .0000
43.0000
.6399 88.8323 98.0000 3.8920 .0000
44.0000
.6680 90.0442 99.0000 3.9867 .0000
45.0000
.6969 91.2522 100.0000
4.0827 .0000
46.0000
.7267 92.4560 101.0000
4.1801 .0000
47.0000
.7573 93.6556 102.0000
4.2789 .0000
48.0000
.7889 94.8505 103.0000
4.3790 .0000
49.0000
.8213 96.0408 104.0000
4.4805 .0000
50.0000
.8546 97.2261 105.0000
4.5834 .0000
51.0000
.8889 98.4063 106.0000
4.6875 .0000
52.0000
.9241 99.5788 107.0000
4.7929 .0000
53.0000
.9603 100.7386 108.0000
4.8991 .0000
54.0000
.9974 101.8806 109.0000
5.0060 .0000
55.0000
1.0357 103.0000 110.0000
5.1132 .0000
______________________________________
TABLE 4
______________________________________
ANGLE (1) (3) (4) F
______________________________________
.0000 .0000 .0000 .0000 36.0000
1.0000 .6283 .4107 .4682 37.0819
2.0000 1.2510 .8105 .9314 38.1840
3.0000 1.8680 1.1997 1.3889
39.3058
4.0000 2.4791 1.5787 1.8399
40.4470
5.0000 3.0842 1.9476 2.2836
41.6070
6.0000 3.6831 2.3070 2.7194
42.7853
7.0000 4.2757 2.6570 3.1467
43.9811
8.0000 4.8618 2.9980 3.5647
45.1939
9.0000 5.4413 3.3303 3.9730
46.4229
10.0000 6.0141 3.6543 4.3710
47.6674
11.0000 6.5800 3.9703 4.7583
48.9265
12.0000 7.1389 4.2786 5.1345
50.1995
13.0000 7.6902 4.5793 5.4993
51.4845
14.0000 8.2317 4.8722 5.8522
52.7770
15.0000 8.7615 5.1572 6.1933
54.0727
16.0000 9.2782 5.4342 6.5226
55.3675
17.0000 9.7804 5.7031 6.8402
56.6577
18.0000 10.2674 5.9642 7.1467
57.9397
19.0000 10.7385 6.2174 7.4422
59.2103
20.0000 11.1926 6.4626 7.7268
60.4646
21.0000 11.6299 6.7003 8.0013
61.7009
22.0000 12.0523 6.9316 8.2675
62.9232
23.0000 12.4619 7.1579 8.5272
64.1364
24.0000 12.8604 7.3801 8.7817
65.3446
25.0000 13.2493 7.5992 9.0324
66.5518
26.0000 13.6299 7.8159 9.2803
67.7617
27.0000 14.0035 8.0310 9.5265
68.9781
28.0000 14.3711 8.2451 9.7718
70.2048
29.0000 14.7336 8.4588 10.0168
71.4449
30.0000 15.0904 8.6715 10.2609
72.6952
31.0000 15.4410 8.8829 10.5032
73.9525
32.0000 15.7850 9.0925 10.7431
75.2136
33.0000 16.1219 9.3002 10.9799
76.4752
34.0000 16.4515 9.5055 11.2132
77.7345
35.0000 16.7737 9.7083 11.4425
78.9889
36.0000 17.0886 9.9087 11.6878
80.2373
37.0000 17.3967 10.1067 11.8891
81.4799
38.0000 17.6984 10.3026 12.1065
82.7171
39.0000 17.9940 10.4965 12.3201
83.9489
40.0000 18.2840 10.6886 12.5299
85.1755
41.0000 18.5688 10.8790 12.7363
86.3977
42.0000 18.8488 11.0681 12.9396
87.6166
43.0000 19.1242 11.2560 13.1397
88.8323
44.0000 19.3950 11.4426 13.3370
90.0442
45.0000 19.6616 11.6281 13.5314
91.2522
46.0000 19.9239 11.8125 13.7230
92.4560
47.0000 20.1821 11.9959 13.9121
93.6556
48.0000 20.4364 12.1783 14.0986
94.8505
49.0000 20.6868 12.3598 14.2827
96.0408
50.0000 20.9335 12.5405 14.4645
97.2261
51.0000 21.1766 12.7203 14.6440
98.4063
52.0000 21.4159 12.8990 14.8211
99.5788
53.0000 21.6506 13.0762 14.9954
100.7386
54.0000 21.8802 13.2514 15.1664
101.8806
55.0000 22.1040 13.4239 15.3337
103.0000
______________________________________
TABLE 5
______________________________________
ANGLE (2) F
______________________________________
.0000 .0000 36.0000
1.0000 .1012 37.0819
2.0000 .2013 38.1840
3.0000 .3004 39.3058
4.0000 .3984 40.4470
5.0000 .4953 41.6070
6.0000 .5911 42.7853
7.0000 .6856 43.9811
8.0000 .7788 45.1939
9.0000 .8708 46.4229
10.0000 .9615 47.6674
11.0000 1.0508 48.9265
12.0000 1.1386 50.1995
13.0000 1.2250 51.4845
14.0000 1.3093 52.7770
15.0000 1.3913 54.0727
16.0000 1.4705 55.3675
17.0000 1.5467 56.6577
18.0000 1.6197 57.9397
19.0000 1.6893 59.2103
20.0000 1.7551 60.4646
21.0000 1.8170 61.7009
22.0000 1.8755 62.9232
23.0000 1.9309 64.1364
24.0000 1.9835 65.3446
25.0000 2.0337 66.5518
26.0000 2.0817 67.7617
27.0000 2.1278 68.9781
28.0000 2.1723 70.2048
29.0000 2.2155 71.4449
30.0000 2.2571 72.6952
31.0000 2.2971 73.9525
32.0000 2.3352 75.2136
33.0000 2.3715 76.4752
34.0000 2.4057 77.7345
35.0000 2.4377 78.9889
36.0000 2.4676 80.2373
37.0000 2.4955 81.4799
38.0000 2.5213 82.7171
39.0000 2.5452 83.9489
40.0000 2.5672 85.1755
41.0000 2.5873 86.3977
42.0000 2.6055 87.6166
43.0000 2.6221 88.8323
44.0000 2.6368 90.0442
45.0000 2.6498 91.2522
46.0000 2.6611 92.4560
47.0000 2.6706 93.6556
48.0000 2.6783 94.8505
49.0000 2.6844 96.0408
50.0000 2.6887 97.2261
51.0000 2.6913 98.4063
52.0000 2.6921 99.5788
53.0000 2.6910 100.7386
54.0000 2.6877 101.8806
55.0000 2.6823 103.0000
______________________________________
EXAMPLE 2
In Example 2, a zoom lens is composed in the order named from the object side, as shown in FIG. 3, of a first lens group G1 of positive refracting power, a second lens group G2 of negative refracting power, a third lens group G3 of positive refracting power, and a fourth lens group G4 of positive refracting power, in which all the lens groups move toward an object along the optical axis during zooming from wide angle to telephoto such that an air gap increases between the first lens group G1 and the second lens group G2, an air gap decreases between the second lens group G2 and the third lens group G3, and an air gap decreases between the third lens group G3 and the fourth lens group G4 and in which the second lens group G2 moves toward the object along the optical axis during focusing.
The construction of each lens group is as follows. The first lens group G1 of positive refracting power is composed of a negative meniscus lens L.sub.1 with convex plane on the object side, a double convex lens L.sub.2 bonded thereto, and a positive meniscus lens L.sub.3 with convex plane on the object side. The second lens group G2 of negative refracting power is composed of a negative meniscus lens L.sub.4 with larger curvature plane on the image side, a double concave negative lens L.sub.5, a positive meniscus lens L.sub.6 bonded thereto, and a positive meniscus lens L.sub.7 with convex plane on the object side. The third lens group G3 of positive refracting power is composed of a double convex positive lens L.sub.8, a double convex positive lens L.sub.9 and a negative lens L.sub.10 bonded thereto. The fourth lens group G4 of positive refracting power is composed of a double convex positive lens L.sub.11 and a negative meniscus lens L.sub.12 with larger curvature plane on the object side.
An aperture stop S is provided on the object side of the third lens group G3 as incorporated with the third lens group G3.
Table 6 shows specifications of the zoom lens in Example 2. In the table of specifications in Example 2, f represents a focal length (mm) and FN an F-number. In Table 6, r represents a radius of curvature of each lens plane (mm), d an interplanar gap between lenses (mm), n and .nu. an index of refraction and an Abbe's number of each lens. Accompanying numerals to the characters represent orders counted from the object side.
The middle portion of Table 6 shows values of coefficients defining the shape of an aspherical surface formed on the lens plane r.sub.6 on the object side in second lens group G2 and the shape of an aspherical surface formed on the lens plane r.sub.22 on the object side of negative lens L.sub.12 in fourth lens group G4. In the middle portion there are described in order from the left, values of the conical constant k and the aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order, A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10. E.sub.-n means 10.sup.-n in the values of aspherical coefficients.
The lower portion in Table 6 shows gaps between lens groups and feed amounts for focusing for each photographic distance of infinity and 600.0 mm at three zooming positions (f=28.8, 50.0, and 82.5 mm) between wide angle end and telephoto end.
The bottom portion shows focal lengths of the lens groups, a lateral magnification of the second lens group G2 at the wide angle end to infinity, and values corresponding to the conditions of the present invention.
The top portion of FIG. 3 is a drawing to show the lens construction of Example 2 according to the present invention, and the middle portion of FIG. 3 shows movement loci (g.sub.1, g.sub.2, g.sub.3, g.sub.4) of the lens groups during zooming with variable of rotation angle of the rotation barrel. Table 7 shows numerical values defining the movement loci. In Table 7, the left end column shows rotation angles .theta. (ANGLE) of rotation barrel, the right end column focal lengths (F), and four columns between the two end columns movement amounts of the lens groups along the optical axis.
As shown in the table, a rotation angle .theta. for zooming from the wide angle end to the telephoto end is set to 55.degree. in this example in the same manner as in Example 1.
The bottom portion of FIG. 3 shows cam shapes actually formed on the rotation barrel of zoom lens according to the present invention. In FIG. 3, g.sub.2F denotes the focus cam for second lens group which is the focusing lens group, g.sub.1Z, g.sub.3Z end g.sub.4Z the zoom cams for first lens group, third lens group and fourth lens group, and g.sub.H the compensating zoom cam common to all the lens groups.
During actual zooming, the movement locus g.sub.2 of second lens group which is the focusing lens group is formed by a combination of the focus cam g.sub.2F with the compensating zoom cam g.sub.H. Also, the moving loci g.sub.1, g.sub.3 and g.sub.4 of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam g.sub.H.
Table 8 shows numerical values defining the cam locus of the focus cam g.sub.2F. In Table 8, the left end column and the fourth column show rotation angles .theta. (ANGLE) of the rotation barrel, the second column and the fifth column movement amounts of the second lens group along the optical axis, and the third column and the right end column focal lengths (F). In the table, the rotation angle .theta. of rotation barrel of the focus cam g.sub.2F is set to 110.degree., which is a double of the rotation angle 55.degree. for zooming in the same manner as in Example 1.
Table 9 shows numerical values defining the cam locus of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group G1, third lens group G3 and fourth lens group G4. In Table 9, the left end column shows rotation angles .theta. (ANGLE) of the rotation barrel, the right end column focal lengths (F), and three columns between the two end columns movement amounts of the lens groups along the optical axis. The rotation angle .theta. for zooming from the wide angle end to the telephoto end is set to 55.degree. identical to that in Table 7.
Table 10 shows numerical values defining the cam locus of the compensating zoom cam g.sub.H common to all the lens groups. In Table 10, the left end column shows rotation angles .theta. (ANGLE) of the rotation barrel, the second column movement amounts of all the lens groups along the optical axis, and the right end column focal lengths (F).
As described above, during actual zooming, the movement locus g.sub.2 of the second lens group which is the focusing lens group is formed by a combination of the focus cam g.sub.2F with the compensating zoom cam g.sub.H, and the movement loci g.sub.1, g.sub.3 and g.sub.4 of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam g.sub.H. Therefore, if the movement amounts along the optical axis in Table 8 and Table 9 are added to the movement amounts along the optical axis in Table 10 in correspondence with each other, the sums should correspond to the movement amounts along the optical axis in Table 7.
TABLE 6
__________________________________________________________________________
f = 28.8-82.5 FN = 3.5-4.6
__________________________________________________________________________
r1 = 150.000
d1 = 1.600
n1 = 1.86074
.nu.1 = 23.0
L1
r2 = 65.662
d2 = 7.500
n2 = 1.51680
.nu.2 = 64.1
L2
r3 = -215.232
d3 = .100
r4 = 38.087
d4 = 4.700
n3 = 1.67025
.nu.3 = 57.6
L3
r5 = 91.398
d5 = 1.970
r6 = 49.175
d6 = 1.500
n4 = 1.74443
.nu.4 = 49.5
L4
r7 = 11.831
d7 = 6.000
r8 = -30.429
d8 = 1.200
n5 = 1.77279
.nu.5 = 49.4
L5
r9 = 21.445
d9 = 2.500
n6 = 1.86074
.nu.6 = 23.0
L6
r10 = 86.170
d10 = .400
r11 = 26.495
d11 = 2.300
n7 = 1.86074
.nu.7 = 23.0
L7
r12 = 46.960
d12 = 14.351
r13 = .000
d13 = 1.500
r14 = 32.464
d14 = 4.000
n8 = 1.50137
.nu.8 = 56.5
L8
r15 = -57.234
d15 = .100
r16 = 22.372
d16 = 5.000
n9 = 1.56384
.nu.9 = 60.8
L9
r17 = -24.520
d17 = 2.000
n10 = 1.80384
.nu.10 = 33.9
L10
r18 = 42.215
d18 = 4.500
r19 = .000
d19 = 6.189
r20 = 39.500
d20 = 6.000
n11 = 1.62041
.nu.11 = 60.3
L11
r21 = -25.592
d21 = 2.300
r22 = -27.661
d22 = 1.800
n12 = 1.86994
.nu.12 = 39.8
L12
r23 = -92.686
d23 = 43.476
__________________________________________________________________________
r6 = .1000E + 01
.0000
-.3172E - 06
-.2020E - 07
-.9068E - 11
-.4289E - 13
r22 = .1000E + 01
.0000
-.2180E - 04
-.3723E - 07
-.1199E - 09
.4587E - 12
__________________________________________________________________________
pos (1)
pos (2)
pos (3)
pos (4)
pos (5)
pos (6)
__________________________________________________________________________
f&b 28.800
50.000
82.500
-.055 -.090
-.135
d0 .000
.000 .000
479.014
463.709
449.283
d5 1.970
13.433
23.791
1.011 11.831
20.879
d12 14.351
7.912 3.354
15.310 9.514
6.265
d19 6.189
4.311 3.311
6.189 4.311
3.311
d23 43.476
55.635
65.261
43.476 55.635
65.261
__________________________________________________________________________
F (1) (2) (3) (4) R (mm)
__________________________________________________________________________
1 28.8000
.0000 .9590
.0000 .0000
600.00
2 50.0000
.0000 1.6022
.0000 .0000
600.00
3 82.5000
.0000 2.9112
.0000 .0000
600.00
__________________________________________________________________________
f1 = 74.000
f2 = -14.650
f3 = 39.000
f4 = 51.000
.beta. = -.293
__________________________________________________________________________
(1) 5.05
(2) 2.73
(3) 17.86
(4) 1.31
TABLE 7
______________________________________
ANGLE (1) (2) (3) (4) F
______________________________________
.0000 .0000 .0000 .0000 .0000 28.8000
1.0000
.7181 .1366 .5387 .6296 29.6363
2.0000
1.4349 .2741 1.0665 1.2568
30.4908
3.0000
2.1510 .4136 1.5845 1.8807
31.3629
4.0000
2.8666 .5564 2.0941 2.5004
32.2517
5.0000
3.5824 .7036 2.5968 3.1150
33.1567
6.0000
4.2989 .8565 3.0939 3.7238
34.0767
7.0000
5.0167 1.0163 3.5869 4.3259
35.0109
8.0000
5.7361 1.1840 4.0770 4.9206
35.9578
9.0000
6.4551 1.3588 4.5632 5.5061
36.9150
10.0000
7.1708 1.5391 5.0437 6.0808
37.8795
11.0000
7.8809 1.7239 5.5173 6.6433
38.8487
12.0000
8.5833 1.9115 5.9827 7.1924
39.8200
13.0000
9.2767 2.1011 6.4392 7.7279
40.7924
14.0000
9.9609 2.2918 6.8869 8.2502
41.7660
15.0000
10.6354 2.4827 7.3254 8.7594
42.7406
16.0000
11.2997 2.6731 7.7546 9.2559
43.7160
17.0000
11.9536 2.8623 8.1744 9.7398
44.6922
18.0000
12.5965 3.0496 8.5846 10.2115
45.6691
19.0000
13.2283 3.2344 8.9850 10.6712
46.6467
20.0000
13.8488 3.4161 9.3755 11.1193
47.6251
21.0000
14.4576 3.5944 9.7561 11.5560
48.6042
22.0000
15.0545 3.7687 10.1268 11.9815
49.5840
23.0000
15.6397 3.9388 10.4875 12.3963
50.5648
24.0000
16.2141 4.1048 10.8391 12.8013
51.5479
25.0000
16.7789 4.2674 11.1829 13.1974
52.5350
26.0000
17.3343 4.4266 11.5190 13.5849
53.5257
27.0000
17.8804 4.5827 11.8480 13.9637
54.5195
28.0000
18.4171 4.7358 12.1700 14.3341
55.5158
29.0000
18.9445 4.8860 12.4854 14.6961
56.5143
30.0000
19.4628 5.0334 12.7945 15.0500
57.5143
31.0000
19.9720 5.1782 13.0974 15.3957
58.5155
32.0000
20.4722 5.3205 13.3946 15.7336
59.5176
33.0000
20.9636 5.4603 13.6861 16.0636
60.5199
34.0000
21.4463 5.5978 13.9723 16.3862
61.5226
35.0000
21.9202 5.7327 14.2531 16.7014
62.5251
36.0000
22.3854 5.8651 14.5285 17.0096
63.5275
37.0000
22.8417 5.9949 14.7987 17.3107
64.5295
38.0000
23.2893 6.1219 15.0636 17.6051
65.5308
39.0000
23.7284 6.2463 15.3234 17.8930
66.5317
40.0000
24.1588 6.3679 15.5781 18.1745
67.5316
41.0000
24.5809 6.4869 15.8280 18.4500
68.5311
42.0000
24.9949 6.6031 16.0731 18.7197
69.5304
43.0000
25.4013 6.7168 16.3139 18.9840
70.5303
44.0000
25.8005 6.8281 16.5506 19.2434
71.5316
45.0000
26.1937 6.9374 16.7839 19.4985
72.5364
46.0000
26.5815 7.0448 17.0143 19.7499
73.5463
47.0000
26.9639 7.1505 17.2419 19.9976
74.5611
48.0000
27.3402 7.2542 17.4664 20.2411
75.5780
49.0000
27.7092 7.3557 17.6870 20.4797
76.5938
50.0000
28.0702 7.4549 17.9033 20.7131
77.6055
51.0000
28.4223 7.5515 18.1150 20.9406
78.6100
52.0000
28.7650 7.6454 18.3216 21.1619
79.6046
53.0000
29.0975 7.7365 18.5227 21.3766
80.5862
54.0000
29.4194 7.8247 18.7181 21.5845
81.5523
55.0000
29.7302 7.9097 18.9074 21.7851
82.5002
______________________________________
TABLE 8
______________________________________
ANGLE (2) F ANGLE (2) F
______________________________________
.0000 .0000 28.8000
1.0000 .0088 29.6363 56.0000 .9905 .0000
2.0000 .0177 30.4908 57.0000 1.0226
.0000
3.0000 .0266 31.3629 58.0000 1.0555
.0000
4.0000 .0355 32.2517 59.0000 1.0891
.0000
5.0000 .0446 33.1567 60.0000 1.1234
.0000
6.0000 .0537 34.0767 61.0000 1.1586
.0000
7.0000 .0629 35.0109 62.0000 1.1945
.0000
8.0000 .0723 35.9578 63.0000 1.2312
.0000
9.0000 .0819 36.9150 64.0000 1.2687
.0000
10.0000 .0917 37.8795 65.0000 1.3070
.0000
11.0000 .1018 38.8487 66.0000 1.3460
.0000
12.0000 .1123 39.8200 67.0000 1.3858
.0000
13.0000 .1231 40.7924 68.0000 1.4263
.0000
14.0000 .1343 41.7660 69.0000 1.4676
.0000
15.0000 .1460 42.7406 70.0000 1.5097
.0000
16.0000 .1579 43.7160 71.0000 1.5525
.0000
17.0000 .1703 44.6922 72.0000 1.5961
.0000
18.0000 .1831 45.6691 73.0000 1.6405
.0000
19.0000 .1963 46.6467 74.0000 1.6857
.0000
20.0000 .2098 47.6251 75.0000 1.7318
.0000
21.0000 .2238 48.6042 76.0000 1.7786
.0000
22.0000 .2382 49.5840 77.0000 1.8262
.0000
23.0000 .2530 50.5648 78.0000 1.8747
.0000
24.0000 .2681 51.5479 79.0000 1.9239
.0000
25.0000 .2835 52.5350 80.0000 1.9740
.0000
26.0000 .2992 53.5257 81.0000 2.0248
.0000
27.0000 .3152 54.5195 82.0000 2.0765
.0000
28.0000 .3315 55.5158 83.0000 2.1290
.0000
29.0000 .3482 56.5143 84.0000 2.1823
.0000
30.0000 .3654 57.5143 85.0000 2.2365
.0000
31.0000 .3830 58.5155 86.0000 2.2915
.0000
32.0000 .4010 59.5176 87.0000 2.3474
.0000
33.0000 .4196 60.5199 88.0000 2.4043
.0000
34.0000 .4386 61.5226 89.0000 2.4620
.0000
35.0000 .4581 62.5251 90.0000 2.5205
.0000
36.0000 .4782 63.5275 91.0000 2.5800
.0000
37.0000 .4987 64.5295 92.0000 2.6403
.0000
38.0000 .5197 65.5308 93.0000 2.7014
.0000
39.0000 .5413 66.5317 94.0000 2.7633
.0000
40.0000 .5633 67.5316 95.0000 2.8260
.0000
41.0000 .5858 68.5311 96.0000 2.8896
.0000
42.0000 .6088 69.5304 97.0000 2.9540
.0000
43.0000 .6323 70.5303 98.0000 3.0192
.0000
44.0000 .6563 71.5316 99.0000 3.0854
.0000
45.0000 .6809 72.5364 100.0000 3.1526
.0000
46.0000 .7060 73.5463 101.0000 3.2208
.0000
47.0000 .7317 74.5611 102.0000 3.2902
.0000
48.0000 .7579 75.5780 103.0000 3.3605
.0000
49.0000 .7847 76.5938 104.0000 3.4317
.0000
50.0000 .8122 77.6055 105.0000 3.5037
.0000
51.0000 .8402 78.6100 106.0000 3.5763
.0000
52.0000 .8689 79.6046 107.0000 3.6493
.0000
53.0000 .8983 80.5862 108.0000 3.7227
.0000
54.0000 .9283 81.5523 109.0000 3.7964
.0000
55.0000 .9590 82.5002 110.0000 3.8702
.0000
______________________________________
TABLE 9
______________________________________
ANGLE (1) (3) (4) F
______________________________________
.0000 .0000 .0000 .0000 28.8000
1.0000 .5903 .4110 .5018 29.6353
2.0000 1.1785 .8101 1.0004
30.4908
3.0000 1.7639 1.1975 1.4937
30.3629
4.0000 2.3458 1.5733 1.9795
32.2517
5.0000 2.9233 1.9377 2.4560
33.1567
6.0000 3.4960 2.2910 2.9210
34.0767
7.0000 4.0633 2.6335 3.3725
35.0109
8.0000 4.6244 2.9653 3.8089
35.9578
9.0000 5.1782 3.2863 4.2293
36.9150
10.0000 5.7233 3.5963 4.6334
37.8795
11.0000 6.2589 3.8953 5.0213
38.8487
12.0000 6.7840 4.1834 5.3932
39.8200
13.0000 7.2987 4.4612 5.7499
40.7924
14.0000 7.8035 4.7294 6.0928
41.7660
15.0000 8.2986 4.9887 6.4227
42.7406
16.0000 8.7846 5.2395 6.7407
43.7160
17.0000 9.2616 5.4825 7.0479
44.6922
18.0000 9.7301 5.7181 7.3450
45.6691
19.0000 10.1903 5.9469 7.6332
46.6467
20.0000 10.6425 6.1692 7.9130
47.6251
21.0000 11.0870 6.3856 8.1854
48.6042
22.0000 11.5241 6.5963 8.4510
49.5840
23.0000 11.9540 6.8017 8.7108
50.5648
24.0000 12.3774 7.0025 8.9646
51.5479
25.0000 12.7951 7.1990 9.2136
52.5350
26.0000 13.2069 7.3916 9.4575
53.5257
27.0000 13.6128 7.5805 9.6962
54.5195
28.0000 14.0128 7.7658 9.9298
55.5158
29.0000 14.4068 7.9477 10.1584
56.5143
30.0000 14.7947 8.1264 10.3819
57.5143
31.0000 15.1767 8.3022 10.6004
58.5155
32.0000 15.5528 8.4751 10.8141
59.5176
33.0000 15.9228 8.6454 11.0229
60.5199
34.0000 16.2871 8.8131 11.2270
61.5226
35.0000 16.6456 6.9785 11.4269
62.5251
36.0000 16.9984 9.1416 11.6226
63.5275
37.0000 17.3456 9.3025 11.8145
64.5295
38.0000 17.6871 9.4614 12.0029
65.5308
39.0000 18.0233 9.6183 12.1879
66.5317
40.0000 18.3541 9.7734 12.3698
67.5316
41.0000 18.6798 9.9269 12.5489
68.5311
42.0000 19.0005 10.0788 12.7253
69.5304
43.0000 19.3167 10.2293 12.8995
70.5303
44.0000 19.6287 10.3787 13.0716
71.5316
45.0000 19.9372 10.5274 13.2420
72.5364
46.0000 20.2427 10.6755 13.4111
73.5463
47.0000 20.5451 10.8231 13.5788
74.5611
48.0000 20.8439 10.9701 13.7448
75.5780
49.0000 21.1382 11.1160 13.9087
76.5938
50.0000 21.4274 11.2606 14.0703
77.6055
51.0000 21.7110 11.4037 14.2293
78.6100
52.0000 21.9885 11.5451 14.3854
79.6046
53.0000 22.2593 11.6845 14.5384
80.5862
54.0000 22.5231 11.8217 14.6881
81.5523
55.0000 22.7795 11.9567 14.8344
82.5002
______________________________________
TABLE 10
______________________________________
ANGLE (2) F
______________________________________
.0000 .0000 28.8000
1.0000 .1278 29.6363
2.0000 .2564 30.4908
3.0000 .3870 31.3629
4.0000 .5209 32.2517
5.0000 .6591 33.1567
6.0000 .8028 34.0767
7.0000 .9534 35.0109
8.0000 1.1117 35.9578
9.0000 1.2769 36.9150
10.0000 1.4475 37.8795
11.0000 1.6220 38.8487
12.0000 1.7992 39.8200
13.0000 1.9780 40.7924
14.0000 2.1574 41.7660
15.0000 2.3367 42.7406
16.0000 2.5152 43.7160
17.0000 2.6920 44.6922
18.0000 2.8665 45.6691
19.0000 3.0381 46.6467
20.0000 3.2063 47.6251
21.0000 3.3706 48.6042
22.0000 3.5305 49.5840
23.0000 3.6858 50.5648
24.0000 3.8367 51.5479
25.0000 3.9838 52.5350
26.0000 4.1274 53.5257
27.0000 4.2675 54.5195
28.0000 4.4043 55.5158
29.0000 4.5378 56.5143
30.0000 4.6680 57.5143
31.0000 4.7953 58.5155
32.0000 4.9195 59.5176
33.0000 5.0408 60.5199
34.0000 5.1592 61.5226
35.0000 5.2746 62.5251
36.0000 5.3869 63.5275
37.0000 5.4962 64.5295
38.0000 5.6022 65.5308
39.0000 5.7051 66.5317
40.0000 5.8047 67.5316
41.0000 5.9011 68.5311
42.0000 5.9944 69.5304
43.0000 6.0845 70.5303
44.0000 6.1718 71.5316
45.0000 6.2565 72.5364
46.0000 6.3388 73.5463
47.0000 6.4188 74.5611
48.0000 6.4963 75.5780
49.0000 6.5710 76.5938
50.0000 6.6427 77.6055
51.0000 6.7113 78.6100
52.0000 6.7765 79.6046
53.0000 6.8382 80.5862
54.0000 6.8963 81.5523
55.0000 6.9507 82.5002
______________________________________
EXAMPLE 3
In Example 3, a zoom lens is composed in the order named from the object side, as shown in FIG. 4, of a first lens group G1 of positive refracting power, a second lens group G2 of negative refracting power, a third lens group G3 of positive refracting power, and a fourth lens group G4 of positive refracting power, in which all the lens groups move toward an object along the optical axis during zooming from wide angle to telephoto such that an air gap increases between the first lens group G1 and the second lens group G2, an air gap decreases between the second lens group G2 and the third lens group G3, and an air gap decreases between the third lens group G3 and the fourth lens group G4 and in which the second lens group G2 moves toward the object along the optical axis during focusing.
The construction of each lens group is as follows. The first lens group G1 of positive refracting power is composed of a negative meniscus lens L.sub.1 with convex plane on the object side, a double convex lens L.sub.2 bonded thereto, and a positive meniscus lens L.sub.3 with convex plane on the object side. The second lens group G2 of negative refracting power is composed of a negative meniscus lens L.sub.4 with larger curvature plane on the image side, a positive meniscus lens L.sub.5 with larger curvature plane on the image side, a double concave negative lens L.sub.6 bonded thereto, and a positive meniscus lens L.sub.7 with convex plane on the object side. The third lens group G3 of positive refracting power is composed of a double convex positive lens L.sub.8, a double convex positive lens L.sub.9 and a negative lens L.sub.10 bonded thereto. The fourth lens group G4 of positive refracting power is composed of a double convex positive lens L.sub.11 a negative meniscus lens L.sub.12 with larger curvature plane on the image side, a double convex positive lens L.sub.13 bonded thereto, and a negative meniscus lens L.sub.14 with larger curvature plane on the object side. An aperture stop S is provided on the object side of the third lens group G3 as incorporated with the third lens group G3.
Table 11 shows specifications of the zoom lens in Example 3. In the table of specifications in Example 3, f represents a focal length (mm) and FN an F-number. In Table 11, r represents a radius of curvature of each lens plane (mm), d an interplanar gap between lenses (mm), n and .nu. an index of refraction and an Abbe's number of each lens. Accompanying numerals to the characters represent orders counted from the object side.
The middle portion of Table 11 shows values of coefficients defining the shape of an aspherical surface formed on the lens plane r.sub.6 on the object side in second lens group G2. In the middle portion there are described in order from the left, values of the conical constant k and the aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order, A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10. E.sub.-n means 10.sup.-n in the values of aspherical coefficients.
The lower portion in Table 11 shows gaps between lens groups and feed amounts for focusing for each photographic distance of infinity and 800.0 mm at three zooming positions (f=36.0, 70.0, and 131.0 mm) between wide angle end and telephoto end.
The bottom portion shows focal lengths of the lens groups, a lateral magnification of the second lens group G2 at the wide angle end to infinity, and values corresponding to the conditions of the present invention.
The top portion of FIG. 4 is a drawing to show the lens construction of Example 3 according to the present invention, and the middle portion of FIG. 4 shows movement loci (g.sub.1, g.sub.2, g.sub.3, g.sub.4) of the lens groups during zooming with variable of rotation angle of the rotation barrel. Table 12 shows numerical values defining the movement loci. In Table 12, the left end column shows rotation angles .theta. (ANGLE) of rotation barrel, the right end column focal lengths (F), and four columns between the two end columns movement amounts of the lens groups along the optical axis.
As shown in the table, a rotation angle .theta. for zooming from the wide angle end to the telephoto end is set to 55.degree. in this example in the same manner as in Example 1.
The bottom portion of FIG. 4 shows cam shapes actually formed on the rotation barrel of zoom lens according to the present invention. In FIG. 4, g.sub.2F denotes the focus cam for second lens group which is the focusing lens group, g.sub.1Z, g.sub.3Z and g.sub.4Z the zoom cams for first lens group, third lens group and fourth lens group, and g.sub.H the compensating zoom cam common to all the lens groups.
During actual zooming, the movement locus g.sub.2 of second lens group which is the focusing lens group is formed by a combination of the focus cam g.sub.2F with the compensating zoom cam g.sub.H. Also, the moving loci .sub.1, g.sub.3 and g.sub.4 of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam g.sub.H.
Table 13 shows numerical values defining the cam locus of the focus cam g.sub.2F. In Table 13, the left end column and the fourth column show rotation angles .theta. (ANGLE) of the rotation barrel, the second column and the fifth column movement amounts of the second lens group along the optical axis, and the third column and the right end column focal lengths (F). In the table, the rotation angle .theta. of rotation barrel of the focus cam g.sub.2F is set to 110.degree., which is a double of the rotation angle 55.degree. for zooming in the same manner as in Example 1.
Table 14 shows numerical values defining the cam locus of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group G1, third lens group G3 and fourth lens group G4. In Table 14, the left end column shows rotation angles .theta. (ANGLE) of rotation barrel, the right end column focal lengths (F), and three columns between the two end columns movement amounts of the lens groups along the optical axis. The rotation angle .theta. for zooming from the wide angle end to the telephoto end is set to 55.degree. identical to that in Table 12.
Table 15 shows numerical values defining the cam locus of the compensating zoom cam g.sub.H common to all the lens groups. In Table 15, the left end column shows rotation angles .theta. (ANGLE) of the rotation barrel, the second column movement amounts of all the lens groups along the optical axis, and the right end column focal lengths (F).
As described above, during actual zooming, the movement locus g.sub.2 of the second lens group which is the focusing lens group is formed by a combination of the focus cam g.sub.2F with the compensating zoom cam g.sub.H, and the movement loci g.sub.1, g.sub.3 and g.sub.4 of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam g.sub.H. Therefore, if the movement amounts along the optical axis in Table 13 and Table 14 are added to the movement amounts along the optical axis in Table 15 in correspondence with each other, the sums should correspond to the movement amounts along the optical axis in Table 12.
TABLE 11
__________________________________________________________________________
f = 36.0-131.0 FN = 3.6-4.6
__________________________________________________________________________
r1 = 130.884
d1 = 1.400
n1 = 1.80518
.nu.1 = 25.4
L1
r2 = 58.027
d2 = 9.700
n2 = 1.51860
.nu.2 = 70.1
L2
r3 = -157.126
d3 = .100
r4 = 39.031
d4 = 5.500
n3 = 1.61720
.nu.3 = 54.0
L3
r5 = 91.293
d5 = 2.639
r6 = 72.574
d6 = 1.500
n4 = 1.77279
.nu.4 = 49.4
L4
r7 = 14.850
d7 = 5.500
r8 = -25.147
d8 = 2.700
n5 = 1.80518
.nu.5 = 25.4
L5
r9 = -18.882
d9 = 1.200
n6 = 1.74810
.nu.6 = 52.3
L6
r10 = 70.764
d10 = .500
r11 = 38.956
d11 = 2.500
n7 = 1.86074
.nu.7 = 23.0
L7
r12 = 731.283
d12 = 18.243
r13 = .000
d13 = 1.300
r14 = 158.779
d14 = 2.500
n8 = 1.61272
.nu.8 = 58.6
L8
r15 = -66.107
d15 = .100
r16 = 26.962
d16 = 6.000
n9 = 1.51680
.nu.9 = 64.1
L9
r17 = -25.683
d17 = 1.500
n10 = 1.80384
.nu.10 = 33.9
L10
r18 = -11035.229
d18 = 14.933
r19 = 36.870
d19 = 4.500
n11 = 1.51860
.nu.11 = 70.1
L11
r20 = -39.884
d20 = 3.000
r21 = 233.745
d21 = 1.500
n12 = 1.79668
.nu.12 = 45.4
L12
r22 = 17.542
d22 = 6.000
n13 = 1.61266
.nu.13 = 44.4
L13
r23 = -72.148
d23 = 3.000
r24 = -17.423
d24 = 1.500
n14 = 1.80384
.nu.14 = 33.9
L14
r25 = -32.268
d25 = 42.711
__________________________________________________________________________
r6 = .1000E + 01
.0000
-.2147E - 05
-.2368E - 07
.1275E - 09
-.4418E - 12
__________________________________________________________________________
pos (1)
pos (2)
pos (3)
pos (4)
pos (5)
pos (6)
__________________________________________________________________________
f&b 36.000
70.000
131.001
-.050 -.088 -.124
d0 .000 .000 .000 659.974
643.460
633.061
d5 2.639 17.599
29.195
1.554 15.088
22.327
d12 18.243
10.076
2.206 19.327
12.587
9.074
d18 14.932
12.214
11.088
14.932
12.214
11.088
d25 42.712
55.151
62.950
42.712
55.151
62.950
__________________________________________________________________________
F (1) (2) (3) (4) R (mm)
__________________________________________________________________________
1 36.0000
.0000
1.0847
.0000 .0000 800.00
2 70.0000
.0000
2.5108
.0000 .0000 800.00
3 131.0000
.0000
6.8683
.0000 .0000 800.00
__________________________________________________________________________
f1 = 71.987
f2 = -16.498
f3 = 44.471
f4 = 80.047
.beta. = -.367
__________________________________________________________________________
(1) 4.36
(2) 2.75
(3) 22.41
(4) 1.80
TABLE 12
______________________________________
ANGLE (1) (2) (3) (4) F
______________________________________
.0000 .0000 .0000 .0000 .0000 35.9993
1.0000 1.1617 .1179 .7074 .8493 37.5924
2.0000 2.3159 .2349 1.4008 1.6943 39.2535
3.0000 3.4540 .3498 2.0768 2.5297 40.9754
4.0000 4.5695 .4620 2.7337 3.3517 42.7517
5.0000 5.6573 .5706 3.3703 4.1574 44.5764
6.0000 6.7139 .6754 3.9860 4.9447 46.4440
7.0000 7.7367 .7759 4.5807 5.7121 48.3493
8.0000 8.7241 .8720 5.1546 6.4585 50.2874
9.0000 9.6750 .9634 5.7079 7.1829 52.2536
10.0000
10.5890 1.0500 6.2403 7.8832 54.2417
11.0000
11.4659 1.1314 6.7516 8.5577 56.2460
12.0000
12.3060 1.2077 7.2421 9.2053 58.2612
13.0000
13.1101 1.2789 7.7124 9.8256 60.2827
14.0000
13.8790 1.3451 8.1632 10.4186
62.3065
15.0000
14.6139 1.4064 8.5953 10.9843
64.3288
16.0000
15.3159 1.4630 9.0094 11.5234
66.3462
17.0000
15.9884 1.5151 9.4066 12.0365
68.3562
18.0000
16.6266 1.5629 9.7877 12.5243
70.3557
19.0000
17.2384 1.6074 10.1544
12.9885
72.3438
20.0000
17.8250 1.6505 10.5098
13.4318
74.3206
21.0000
18.3890 1.6939 10.8567
13.8567
76.2867
22.0000
18.9331 1.7391 11.1974
14.2654
78.2425
23.0000
19.4592 1.7872 11.5337
14.6598
80.1883
24.0000
19.9693 1.8392 11.8670
15.0414
82.1241
25.0000
20.4651 1.8957 12.1988
15.4118
84.0499
26.0000
20.9480 1.9573 12.5297
15.7722
85.9662
27.0000
21.4138 2.0188 12.8541
16.1197
87.8672
28.0000
21.8544 2.0710 13.1614
16.4482
89.7427
29.0000
22.2646 2.1079 13.4445
16.7541
91.5851
30.0000
22.6424 2.1266 13.7004
17.0358
93.3903
31.0000
22.9882 2.1267 13.9292
17.2938
95.1567
32.0000
23.3038 2.1097 14.1327
17.5294
96.8851
33.0000
23.5923 2.0773 14.3137
17.7449
98.5783
34.0000
23.8566 2.0318 14.4751
17.9425
100.2404
35.0000
24.0997 1.9752 14.6199
18.1243
101.8751
36.0000
24.3241 1.9092 14.7506
18.2923
103.4861
37.0000
24.5321 1.8354 14.8693
18.4481
105.0768
38.0000
24.7258 1.7554 14.9784
18.5934
106.6503
39.0000
24.9075 1.6710 15.0800
18.7297
108.2088
40.0000
25.0788 1.5840 15.1759
18.8583
109.7520
41.0000
25.2408 1.4954 15.2675
18.9600
111.2791
42.0000
25.3945 1.4062 15.3555
19.0955
112.7895
43.0000
25.5409 1.3173 15.4411
19.2055
114.2819
44.0000
25.6805 1.2290 15.5245
19.3104
115.7568
45.0000
25.8141 1.1417 15.6063
19.4109
117.2156
46.0000
25.9423 1.0556 15.6870
19.5074
118.6598
47.0000
26.0858 .9708 15.7669
19.6003
120.0904
48.0000
26.1848 .8875 15.8463
19.6899
121.5086
49.0000
26.3000 .8057 15.9255
19.7766
122.9155
50.0000
26.4116 .7254 16.0046
19.8606
124.3123
51.0000
26.5199 .6469 16.0838
19.9421
125.6989
52.0000
26.6245 .5703 16.1629
20.0209
127.0695
53.0000
26.7254 .4963 16.2412
20.0968
128.4155
54.0000
26.8218 .4252 16.3185
20.1694
129.7284
55.0000
26.9135 .3575 16.3942
20.2384
130.9999
______________________________________
TABLE 13
______________________________________
ANGLE (2) F ANGLE (2) F
______________________________________
.0000 .0000 35.9993
1.0000 .0034 37.5924 56.0000 1.1422 .0000
2.0000 .0069 39.2535 57.0000 1.2034 .0000
3.0000 .0104 40.9754 58.0000 1.2682 .0000
4.0000 .0141 42.7517 59.0000 1.3367 .0000
5.0000 .0178 44.5764 60.0000 1.4086 .0000
6.0000 .0218 46.4440 61.0000 1.4839 .0000
7.0000 .0259 48.3493 62.0000 1.5625 .0000
8.0000 .0303 50.2874 63.0000 1.6444 .0000
9.0000 .0349 52.2536 64.0000 1.7294 .0000
10.0000
.0398 54.2417 65.0000 1.8175 .0000
11.0000
.0451 56.2460 66.0000 1.9086 .0000
12.0000
.0507 58.2612 67.0000 2.0026 .0000
13.0000
.0567 60.2827 68.0000 2.0994 .0000
14.0000
.0632 62.3065 69.0000 2.1989 .0000
15.0000
.0701 64.3288 70.0000 2.3011 .0000
16.0000
.0775 66.3462 71.0000 2.4059 .0000
17.0000
.0854 68.3562 72.0000 2.5132 .0000
18.0000
.0939 70.3557 73.0000 2.6229 .0000
19.0000
.1030 72.3438 74.0000 2.7349 .0000
20.0000
.1127 74.3206 75.0000 2.8492 .0000
21.0000
.1231 76.2867 76.0000 2.9656 .0000
22.0000
.1342 78.2425 77.0000 3.0841 .0000
23.0000
.1460 80.1883 78.0000 3.2046 .0000
24.0000
.1585 82.1241 79.0000 3.3270 .0000
25.0000
.1719 84.0499 80.0000 3.4512 .0000
26.0000
.1861 85.9662 81.0000 3.5772 .0000
27.0000
.2011 87.8672 82.0000 3.7049 .0000
28.0000
.2169 89.7427 83.0000 3.8342 .0000
29.0000
.2335 91.5851 84.0000 3.9650 .0000
30.0000
.2510 93.3903 85.0000 4.0973 .0000
31.0000
.2693 95.1567 86.0000 4.2309 .0000
32.0000
.2885 96.8851 87.0000 4.3660 .0000
33.0000
.3087 98.5783 88.0000 4.5024 .0000
34.0000
.3297 100.2404 89.0000 4.6404 .0000
35.0000
.3519 101.8751 90.0000 4.7802 .0000
36.0000
.3751 103.4861 91.0000 4.9218 .0000
37.0000
.3995 105.0768 92.0000 5.0654 .0000
38.0000
.4251 106.6503 93.0000 5.2113 .0000
39.0000
.4520 108.2088 94.0000 5.3594 .0000
40.0000
.4802 109.7520 95.0000 5.5095 .0000
41.0000
.5099 111.2791 96.0000 5.6616 .0000
42.0000
.5410 112.7893 97.0000 5.8155 .0000
43.0000
.5737 114.2819 98.0000 5.9710 .0000
44.0000
.6079 115.7568 99.0000 6.1282 .0000
45.0000
.6436 117.2156 100.0000
6.2869 .0000
46.0000
.6808 118.6598 101.0000
6.4472 .0000
47.0000
.7194 120.0904 102.0000
6.6090 .0000
48.0000
.7593 121.5086 103.0000
6.7724 .0000
49.0000
.8006 122.9155 104.0000
6.9373 .0000
50.0000
.8433 124.3123 105.0000
7.1038 .0000
51.0000
.8871 125.6989 106.0000
7.2717 .0000
52.0000
.9327 127.0695 107.0000
7.4409 .0000
53.0000
.9805 128.4155 108.0000
7.6110 .0000
54.0000
1.0309 129.7284 109.0000
7.7818 .0000
55.0000
1.0847 130.9999 110.0000
7.9529 .0000
______________________________________
TABLE 14
______________________________________
ANGLE (1) (3) (4) F
______________________________________
.0000 .0000 .0000 .0000 35.9993
1.0000 1.0472 .5929 .7348 37.5924
2.0000 2.0880 1.1728 1.4663
39.2535
3.0000 3.1146 1.7374 2.1903
40.9754
4.0000 4.1216 2.2858 2.9038
42.7517
5.0000 5.1045 2.8175 3.6046
44.5764
6.0000 6.0603 3.3324 4.2910
46.4440
7.0000 6.9868 3.8307 4.9621
48.3493
8.0000 7.8824 4.3129 5.6168
50.2874
9.0000 8.7465 4.7794 6.2544
52.2536
10.0000 9.5788 5.2301 6.8730
54.2417
11.0000 10.3795 5.6652 7.4713
56.2460
12.0000 11.1490 6.0851 8.0483
58.2612
13.0000 11.8879 6.4902 8.6034
60.2827
14.0000 12.5971 6.8813 9.1367
62.3065
15.0000 13.2776 7.2590 9.6480
64.3288
16.0000 13.9305 7.6239 10.1379
66.3462
17.0000 14.5568 7.9769 10.6068
68.5562
18.0000 15.1575 8.3187 11.0553
70.3557
19.0000 15.7340 8.6500 11.4841
72.3438
20.0000 16.2872 8.9721 11.8941
74.3206
21.0000 16.8182 9.2859 12.2859
76.2867
22.0000 17.3281 9.5925 12.6605
78.2425
23.0000 17.8180 9.8925 13.0185
80.1883
24.0000 18.2887 10.1864 13.3608
82.1241
25.0000 18.7413 10.4749 13.6880
84.0499
26.0000 19.1767 10.7585 14.0010
85.9662
27.0000 19.5960 11.0364 14.3019
87.8672
28.0000 20.0003 11.3072 14.5941
89.7427
29.0000 20.3903 11.5701 14.8797
91.5851
30.0000 20.7669 11.8249 15.1603
93.3903
31.0000 21.1308 12.0718 15.4364
95.1567
32.0000 21.4827 12.3116 15.7083
96.8851
33.0000 21.8236 12.5450 15.9762
98.5783
34.0000 22.1545 12.7730 16.2404
100.2404
35.0000 22.4764 12.9966 16.5010
101.8751
36.0000 22.7900 13.2164 16.7582
103.4861
37.0000 23.0961 13.4334 17.0122
105.0768
38.0000 23.3955 13.6480 17.2631
106.6503
39.0000 23.6885 13.8609 17.5107
108.2088
40.0000 23.9751 14.0722 17.7546
109.7520
41.0000 24.2554 14.2820 17.9945
111.2791
42.0000 24.5294 14.4904 18.2303
112.7893
43.0000 24.7973 14.6975 18.4619
114.2819
44.0000 25.0594 14.9034 18.6893
115.7568
45.0000 25.3160 15.1082 18.9128
117.2156
46.0000 25.5575 15.3122 19.1326
118.6598
47.0000 25.8143 15.5155 19.3488
120.0904
48.0000 26.0567 15.7182 19.5618
121.5086
49.0000 26.2950 15.9205 19.7715
122.9155
50.0000 26.5294 16.1225 19.9784
124.3123
51.0000 26.7602 16.3241 20.1824
125.6989
52.0000 26.9870 16.5253 20.3833
127.0695
53.0000 27.2096 16.7254 20.5810
128.4155
54.0000 27.4275 16.9243 20.7751
129.7284
55.0000 27.6407 17.1214 20.9656
130.9999
______________________________________
TABLE 15
______________________________________
ANGLE (2) F
______________________________________
.0000 .0000 35.9993
1.0000 .1145 37.5924
2.0000 .2280 39.2535
3.0000 .3394 40.9754
4.0000 .4479 42.7517
5.0000 .5528 44.5764
6.0000 .6536 46.4440
7.0000 .7500 48.3493
8.0000 .8417 50.2874
9.0000 .9285 52.2536
10.0000 1.0101 54.2417
11.0000 1.0863 56.2460
12.0000 1.1570 58.2612
13.0000 1.2222 60.2827
14.0000 1.2819 62.3065
15.0000 1.3363 64.3288
16.0000 1.3855 66.3462
17.0000 1.4297 68.3562
18.0000 1.4690 70.3557
19.0000 1.5044 72.3438
20.0000 1.5377 74.3206
21.0000 1.5708 76.2867
22.0000 1.6049 78.2425
23.0000 1.6412 80.1883
24.0000 1.6806 82.1241
25.0000 1.7238 84.0499
26.0000 1.7713 85.9662
27.0000 1.8177 87.8672
28.0000 1.8542 89.7427
29.0000 1.8744 91.5851
30.0000 1.8756 93.3903
31.0000 1.8574 95.1567
32.0000 1.8211 96.8851
33.0000 1.7687 98.5783
34.0000 1.7021 100.2404
35.0000 1.6233 101.8751
36.0000 1.5341 103.4861
37.0000 1.4360 105.0768
38.0000 1.3303 106.6503
39.0000 1.2191 108.2088
40.0000 1.1037 109.7520
41.0000 .9855 111.2791
42.000 .8652 112.7893
43.0000 .7436 114.2819
44.0000 .6211 115.7568
45.0000 .4981 117.2156
46.0000 .3748 118.6598
47.0000 .2514 120.0904
48.0000 .1281 121.5086
49.0000 .0050 122.9155
50.0000 -.1178 124.3123
51.0000 -.2403 125.6989
52.0000 -.3624 127.0695
53.0000 -.4842 128.4155
54.0000 -.6058 129.7284
55.0000 -.7272 130.9999
______________________________________
EXAMPLE 4
In Example 4, a zoom lens is composed in the order named from the object side, as shown in FIG. 5, of a first lens group G1 of positive refracting power, a second lens group G2 of negative refracting power, a third lens group G3 of positive refracting power, and a fourth lens group G4 of positive refracting power, in which all the lens groups move toward an object along the optical axis during zooming from wide angle to telephoto such that an air gap increases between the first lens group G1 and the second lens group G2, an air gap decreases between the second lens group G2 and the third lens group G3, and an air gap decreases between the third lens group G3 and the fourth lens group G4 and in which the second lens group G2 moves toward the object along the optical axis during focusing.
The construction of each lens group is as follows. The first lens group G1 of positive refracting power is composed of a negative meniscus lens L.sub.1 with convex plane on the object side, a double convex lens L.sub.2 bonded thereto, and a positive meniscus lens L.sub.3 with convex plane on the object side. The second lens group G2 of negative refracting power is composed of a negative meniscus lens L.sub.4 with larger curvature plane on the image side, a double concave negative lens L.sub.5, a positive meniscus lens L.sub.6 bonded thereto, and a positive meniscus lens L.sub.7 with convex plane on the object side. The third lens group G3 of positive refracting power is composed of a double convex positive lens L.sub.8, a double convex positive lens L.sub.9 and a negative lens L.sub.10 bonded thereto. The fourth lens group G4 of positive refracting power is composed of a double convex positive lens L.sub.11 and a negative meniscus lens L.sub.12 with larger curvature plane on the object side. An aperture stop S is provided on the object side of the third lens group G3 as incorporated with the third lens group
Table 16 shows specifications of the zoom lens in Example 4. In the table of specifications in Example 4, f represents a focal length (mm) and FN an F-number. In Table 16, r represents a radius of curvature of each lens plane (mm), d an interplanar gap between lenses (mm), n and .nu. an index of refraction and an Abbe's number of each lens. Accompanying numerals to the characters represent orders counted from the object side.
The middle portion of Table 16 shows values of coefficients defining the shape of an aspherical surface formed on the lens plane r.sub.6 on the object side in second lens group G2 and the shape of an aspherical surface formed on the lens plane r.sub.22 on the object side of negative lens L.sub.12 in fourth lens group G4. In the middle portion there are described in order from the left values of the conical constant k and the aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order, A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10. E.sub.-n means 10.sup.-n in the values of aspherical coefficients.
The lower portion in Table 16 shows gaps between lens groups and feed amounts for focusing for each photographic distance of infinity and 800.0 mm at three zooming positions (f=28.8, 50.0, and 103.0 mm) between wide angle end and telephoto end.
The bottom portion shows focal lengths of the lens groups, a lateral magnification of the second lens Group G2 at the wide angle end to infinity, and values corresponding to the conditions of the present invention.
The top portion of FIG. 5 is a drawing to show the lens construction of Example 4 according to the present invention, and the middle portion of FIG. 5 shows movement loci (g.sub.1, g.sub.2, g.sub.3, g.sub.4) of the lens groups during zooming with variable of rotation angle of the rotation barrel. Table 17 shows numerical values defining the movement loci. In Table 17, the left end column shows rotation angles .theta. (ANGLE) of rotation barrel, the right end column focal lengths (F), and four columns between the two end columns movement amounts of the lens groups along the optical axis.
As shown in the table, a rotation angle .theta. for zooming from the wide angle end to the telephoto end is set to 55.degree. in this example in the same manner as in Example 1.
The bottom portion of FIG. 5 shows cam shapes actually formed on the rotation barrel of zoom lens according to the present invention. In FIG. 5, g.sub.2F denotes the focus cam for second lens group which is the focusing lens group, g.sub.1Z, g.sub.3Z and g.sub.4Z the zoom cams for first lens group, third lens group and fourth lens group, and g.sub.H the compensating zoom cam common to all the lens groups.
During actual zooming, the movement locus g.sub.2 of second lens group which is the focusing lens group is formed by a combination of the focus cam g.sub.2F with the compensating zoom cam g.sub.H. Also, the moving loci g.sub.1, g.sub.3 and g.sub.4 of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam g.sub.H.
Table 18 shows numerical values defining the cam trace of the focus cam g.sub.2F. In Table 18, the left end column and the fourth column show rotation angles .theta. (ANGLE) of the rotation barrel, the second column and the fifth column movement amounts of the second lens group along the optical axis, and the third column and the right end column focal lengths (F). In the table, the rotation angle .theta. of rotation barrel of the focus cam g.sub.2F is set to 110.degree., which is a double of the rotation angle 55.degree. for zooming in the same manner as in Example 1.
Table 19 shows numerical values defining the cam loci of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group G1, third lens group G3 and fourth lens group G4. In Table 19, the left end column shows rotation angles .theta. (ANGLE) of the rotation barrel, the right end column focal lengths (F), and three columns between the two end columns movement amounts of the lens groups along the optical axis. The rotation angle .theta. for zooming from the wide angle to the telephoto end is set to 55.degree. identical to that in Table 17.
Table 20 shows numerical values defining the cam locus of the compensating zoom cam g.sub.H common to all the lens groups. In Table 20, the left end column shows rotation angles .theta. (ANGLE) of the rotation barrel, the second column movement amounts of all the lens groups along the optical axis, and the right end column focal lengths (F).
As described above, during actual zooming, the movement locus g.sub.2 of the second lens group which is the focusing lens group is formed by a combination of the focus cam g.sub.2F with the compensating zoom cam g.sub.H, and the movement loci g.sub.1, g.sub.3 and g.sub.4 of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of the zoom cams g.sub.1Z, g.sub.3Z and g.sub.4Z of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam g.sub.H. Therefore, if the movement amounts along the optical axis in Table 18 and Table 19 are added to the movement amounts along the optical axis in Table 20 in correspondence with each other, the sums should correspond to the movement amounts along the optical axis in Table 17.
TABLE 16
__________________________________________________________________________
f = 28.8-103.0 FN = 3.5-4.9
__________________________________________________________________________
r1 = 150.000
d1 = 1.600
n1 = 1.86074
.nu.1 = 23.0
L1
r2 = 65.193
d2 = 7.500
n2 = 1.51680
.nu.2 = 64.1
L2
r3 = -201.063
d3 = .100
r4 = 38.552
d4 = 4.700
n3 = 1.67025
.nu.3 = 57.6
L3
r5 = 92.468
d5 = 2.014
r6 = 50.334
d6 = 1.500
n4 = 1.74443
.nu.4 = 49.5
L4
r7 = 11.892
d7 = 6.000
r8 = -30.162
d8 = 1.200
n5 = 1.77279
.nu.5 = 49.4
L5
r9 = 21.082
d9 = 2.500
n6 = 1.86074
.nu.6 = 23.0
L6
r10 = 89.406
d10 = .400
r11 = 26.791
d11 = 2.300
n7 = 1.86074
.nu.7 = 23.0
L7
r12 = 47.408
d12 = 14.581
r13 = .000
d13 = 1.500
r14 = 31.605
d14 = 4.000
n8 = 1.50137
.nu.8 = 56.5
L8
r15 = -56.214
d15 = .100
r16 = 22.191
d16 = 5.000
n9 = 1.56384
.nu.9 = 60.8
L9
r17 = -24.447
d17 = 2.000
n10 = 1.80384
.nu.10 = 33.9
L10
r18 = 39.928
d18 = 4.500
r19 = .000
d19 = 6.093
r20 = 38.981
d20 = 6.000
n11 = 1.62041
.nu.11 = 60.3
L11
r21 = -25.650
d21 = 2.300
r22 = -27.587
d22 = 1.800
n12 = 1.86994
.nu.12 = 39.8
L12
r23 = -93.762
d23 = 43.415
__________________________________________________________________________
r6 = .1000E + 01
.0000
-.1355E - 05
-.1877E - 07
-.5232E - 11
-.7221E - 13
r22 = .1000E + 01
.0000
-.2159E - 04
-.3769E - 07
-.1285E - 09
.4333E - 12
__________________________________________________________________________
pos (1)
pos (2)
pos (3)
pos (4)
pos (5)
pos (6)
__________________________________________________________________________
f&b 28.800
50.000
103.000
-.040 -.066
-.120
d0 .000 .000 .000
678.896
663.592
642.203
d5 2.014
13.477
27.014
1.316 12.289
24.153
d12 14.581
8.142
1.416
15.280 9.329
4.277
d19 6.093
4.215
3.065
6.093 4.215
3.065
d23 43.415
55.574
71.302
43.415 55.574
71.302
__________________________________________________________________________
F (1) (2) (3) (4) R (mm)
__________________________________________________________________________
1 28.8000
.0000
.6983
.0000 .0000
800.00
2 50.0000
.0000
1.1876
.0000 .0000
800.00
3 103.0000
.0000
2.8609
.0000 .0000
800.00
__________________________________________________________________________
f1 = 74.000
f2 = -14.650
f3 = 39.000
f4 = 51.000
.beta. = -.293
__________________________________________________________________________
(1) 5.05
(2) 2.73
(3) 17.86
(4) 1.31
TABLE 17
______________________________________
ANGLE (1) (2) (3) (4) F
______________________________________
.0000 .0000 .0000 .0000 .0000 28.8000
1.0000 .8574 .1623 .6400 .7493 29.7996
2.0000 1.7101 .3257 1.2628 1.4926 30.8214
3.0000 2.5608 .4928 1.8726 2.2307 31.8668
4.0000 3.4121 .6661 2.4734 2.9641 32.9370
5.0000 4.2668 .8482 3.0690 3.6933 34.0333
6.0000 5.1275 1.0420 3.6632 4.4188 35.1565
7.0000 5.9959 1.2492 4.2587 5.1402 36.3064
8.0000 6.8691 1.4683 4.8532 5.8547 37.4802
9.0000 7.7439 1.6972 5.4442 6.5592 38.6744
10.0000
8.6169 1.9334 6.0290 7.2510 39.8855
11.0000
9.4849 2.1745 6.6048 7.9275 41.1103
12.0000
10.3448 2.4181 7.1694 8.5863 42.3452
13.0000
11.1937 2.6617 7.7204 9.2255 43.5875
14.0000
12.0289 2.9031 8.2558 9.8434 44.8339
15.0000
12.8482 3.1404 8.7741 10.4388
46.0819
16.0000
13.6495 3.3715 9.2737 11.0107
47.3293
17.0000
14.4310 3.5951 9.7538 11.5586
48.5738
18.0000
15.1903 3.8095 10.2128
12.0812
49.8115
19.0000
15.9234 4.0130 10.6487
12.5768
51.0361
20.0000
16.6310 4.2057 11.0628
13.0470
52.2481
21.0000
17.3154 4.3882 11.4572
13.4944
53.4501
22.0000
17.9784 4.5613 11.8338
13.9211
54.6449
23.0000
18.6217 4.7254 12.1942
14.3292
55.8349
24.0000
19.2469 4.8811 12.5398
14.7202
57.0224
25.0000
19.8553 5.0288 12.8719
15.0958
58.2093
26.0000
20.4475 5.1688 13.1913
15.4569
59.3965
27.0000
21.0237 5.3013 13.4984
15.8040
60.5838
28.0000
21.5841 5.4264 13.7939
16.1379
61.7711
29.0000
22.1290 5.5445 14.0783
16.4592
62.9584
30.0000
22.6588 5.6557 14.3520
16.7684
64.1454
31.0000
23.1736 5.7603 14.6156
17.0661
65.3320
32.0000
23.6739 5.8586 14.8695
17.3529
66.5184
33.0000
24.1600 5.9507 15.1142
17.6292
67.7042
34.0000
24.6321 6.0370 15.3501
17.8955
68.8888
35.0000
25.0902 6.1176 15.5775
18.1520
70.0716
36.0000
25.5353 6.1933 15.7974
18.3999
71.2528
37.0000
25.9697 6.2666 16.0131
18.6422
72.4356
38.0000
26.3962 6.3399 16.2278
18.8819
73.6234
39.0000
26.8170 6.4154 16.4443
19.1218
74.8199
40.0000
27.2346 6.4953 16.6656
19.3649
76.0285
41.0000
27.6514 6.5818 16.8945
19.6139
77.2538
42.0000
28.0703 6.6773 17.1341
19.8720
78.5006
43.0000
28.4941 6.7846 17.3880
20.1429
79.7746
44.0000
28.9265 6.9070 17.6605
20.4309
81.0828
45.0000
29.3720 7.0489 17.9571
20.7418
82.4345
46.0000
29.8369 7.2164 18.2856
21.0835
83.8426
47.0000
30.3306 7.4186 18.6574
21.4678
85.3261
48.0000
30.8651 7.6676 19.0875
21.9102
86.9107
49.0000
31.4513 7.9738 19.5689
22.4246
88.6215
50.0000
32.1021 8.3504 20.1771
23.0277
90.4872
51.0000
32.8312 8.8122 20.8694
23.7386
92.5380
52.0000
33.6545 9.3764 21.6850
24.5788
94.8091
53.0000
34.5846 10.0563 22.6380
25.5652
97.3310
54.0000
35.6145 10.8456 23.7176
26.6897
100.0948
55.0000
36.6939 11.6940 24.8591
27.8866
102.9995
______________________________________
TABLE 18
______________________________________
ANGLE (2) F ANGLE (2) F
______________________________________
.0000 .0000 28.8000
1.0000
.0057 29.7996 56.0000 .7243 .0000
2.0000
.0114 30.8214 57.0000 .7509 .0000
3.0000
.0172 31.8668 58.0000 .7783 .0000
4.0000
.0229 32.9370 59.0000 .8065 .0000
5.0000
.0287 34.0333 60.0000 .8355 .0000
6.0000
.0345 35.1565 61.0000 .8654 .0000
7.0000
0403 36.3064 62.0000 .8962 .0000
8.0000
.0462 37.4802 53.0000 .9279 .0000
9.0000
.0522 38.6744 64.0000 .9605 .0000
10.0000
.0583 39.8855 65.0000 .9941 .0000
11.0000
.0645 41.1103 66.0000 1.0286
.0000
12.0000
0709 42.3452 67.0000 1.0640
.0000
13.0000
.0775 43.5875 68.0000 1.1004
.0000
14.0000
.0843 44.8339 69.0000 1.1377
.0000
15.0000
.0913 46.0819 70.0000 1.1760
.0000
16.0000
.0986 47.3293 71.0000 1.2153
.0000
17.0000
.1063 48.5738 72.0000 1.2555
.0000
18.0000
.1142 49.8115 73.0000 1.2967
.0000
19.0000
.1226 51.0361 74.0000 1.3388
.0000
20.0000
.1315 52.2481 75.0000 1.3819
.0000
21.0000
.1409 53.4501 76.0000 1.4258
.0000
22.0000
.1506 54.6449 77.0000 1.4707
.0000
23.0000
.1606 55.8349 78.0000 1.5166
.0000
24.0000
.1710 57.0224 79.0000 1.5635
.0000
25.0000
.1816 58.2093 80.0000 1.6113
.0000
26.0000
.1925 59.3965 81.0000 1.6602
.0000
27.0000
.2037 60.5838 82.0000 1.7101
.0000
28.0000
.2152 61.7711 83.0000 1.7611
.0000
29.0000
.2270 62.9584 84.0000 1.8132
.0000
30.0000
.2391 64.1454 85.0000 1.8663
.0000
31.0000
.2516 65.3320 86.0000 1.9205
.0000
32.0000
.2645 66.5184 87.0000 1.9758
.0000
33.0000
.2778 67.7042 88.0000 2.0323
.0000
34.0000
.2916 68.8888 89.0000 2.0899
.0000
35.0000
.3058 70.0716 90.0000 2.1486
.0000
36.0000
.3205 71.2528 91.0000 2.2084
.0000
37.0000
.3357 72.4356 92.0000 2.2693
.0000
38.0000
.3514 73.6234 93.0000 2.3312
.0000
39.0000
.3675 74.8199 94.0000 2.3942
.0000
40.0000
.3840 76.0285 95.0000 2.4583
.0000
41.0000
.4010 77.2538 96.0000 2.5234
.0000
42.0000
.4185 78.5006 97.0000 2.5897
.0000
43.0000
.4365 79.7746 98.0000 2.6570
.0000
44.0000
.4551 81.0828 99.0000 2.7256
.0000
45.0000
.4742 82.4345 100.0000 2.7954
0000
46.0000
.4938 83.8425 101.0000 2.8664
.0000
47.0000
.5140 85.3261 102.0000 2.9387
.0000
48.0000
.5348 86.9107 103.0000 3.0124
.0000
49.0000
.5563 88.6215 104.0000 3.0874
.0000
50.0000
.5784 90.4872 105.0000 3.1639
.0000
51.0000
.6011 92.5380 106.0000 3.2416
.0000
52.0000
.6244 94.8091 107.0000 3.3201
.0000
53.0000
.6484 97.3310 108.0000 3.3995
.0000
54.0000
.6730 100.0948 109.0000 3.4792
.0000
55.0000
.6983 102.9995 110.0000 3.5592
.0000
______________________________________
TABLE 19
______________________________________
ANGLE (1) (3) (4) F
______________________________________
.0000 .0000 .0000 .0000 28.8000
1.0000 .7009 .4834 .5927 29.7996
2.0000 1.3958 .9485 1.1784
30.8214
3.0000 2.0852 1.3970 1.7551
31.8668
4.0000 2.7689 1.8302 2.3210
32.9370
5.0000 5.4472 2.2494 2.8738
34.0333
6.0000 4.1200 2.6558 3.4114
35.1565
7.0000 4.7870 3.0498 5.9314
36.3064
8.0000 5.4470 3.4311 4.4326
37.4802
9.0000 6.0989 3.7992 4.9142
38.6744
10.0000 6.7418 4.1538 5.3759
39.8855
11.0000 7.3749 4.4948 5.8174
41.1103
12.0000 7.9976 4.8222 6.2391
42.3452
13.0000 8.6095 5.1362 6.6413
43.5875
14.0000 9.2101 5.4370 7.0246
44.8339
15.0000 9.7992 5.7251 7.3898
46.0819
16.0000 10.3766 6.0009 7.7378
47.3293
17.0000 10.9422 6.2649 8.0697
48.5738
18.0000 11.4950 6.5175 8.3859
49.8115
19.0000 12.0330 6.7583 8.6864
51.0361
20.0000 12.5569 6.9887 8.9729
52.2481
21.0000 13.0681 7.2099 9.2470
53.4501
22.0000 13.5677 7.4231 9.5104
54.6449
23.0000 14.0570 7.6294 9.7644
55.8349
24.0000 14.5368 7.8297 10.0102
57.0224
25.0000 15.0081 8.0247 10.2486
58.2093
26.0000 15.4712 8.2150 10.4806
59.3965
27.0000 15.9261 8.4008 10.7064
60.5838
28.0000 16.3728 8.5826 10.9266
61.7711
29.0000 16.8115 8.7607 11.1416
62.9584
30.0000 17.2421 8.9354 11.3518
64.1454
31.0000 17.6649 9.1069 11.5574
65.3320
32.0000 18.0798 9.2754 11.7588
66.5184
33.0000 18.4871 9.4413 11.9563
67.7042
34.0000 18.8867 9.6047 12.1501
68.8888
35.0000 19.2784 9.7657 12.3403
70.0716
36.0000 19.6625 9.9246 12.5271
71.2528
37.0000 20.0388 10.0822 12.7113
72.4356
38.0000 20.4076 10.2392 12.8933
75.6234
39.0000 20.7691 10.3964 13.0739
74.8199
40.0000 21.1233 10.5543 13.2535
76.0285
41.0000 21.4706 10.7137 13.4331
77.2538
42.0000 21.8115 10.8753 13.6132
78.5006
43.0000 22.1460 11.0399 13.7948
79.7746
44.0000 22.4746 11.2086 13.9790
81.0828
45.0000 22.7975 11.3824 14.1671
82.4345
46.0000 23.1144 11.5630 14.3609
83.8426
47.0000 23.4260 11.7528 14.5632
85.3261
48.0000 23.7324 11.9548 14.7775
86.9107
49.0000 24.0338 12.1713 15.0070
88.6215
50.0000 24.3301 12.4051 15.2557
90.4872
51.0000 24.6200 12.6582 15.5274
92.5380
52.0000 24.9026 12.9330 15.8268
94.8091
53.0000 25.1767 13.2302 16.1574
97.3310
54.0000 25.4419 13.5450 16.5171
100.0948
55.0000 25.6983 13.8635 16.8910
102.9995
______________________________________
TABLE 20
______________________________________
ANGLE (2) F
______________________________________
.0000 .0000 28.8000
1.0000 .1566 29.7996
2.0000 .3142 30.8214
3.0000 .4756 31.8668
4.0000 .6432 32.9370
5.0000 .8195 34.0333
6.0000 1.0075 35.1565
7.0000 1.2089 36.3064
5.0000 1.4221 37.4802
9.0000 1.6450 38.6744
10.0000 1.8751 39.8855
11.0000 2.1100 41.1103
12.0000 2.3472 42.3452
13.0000 2.5842 45.5875
14.0000 2.8189 44.8339
15.0000 3.0490 46.0819
16.0000 3.2729 47.3293
17.0000 3.4889 48.5738
18.0000 3.6953 49.8115
19.0000 3.8903 51.0361
20.0000 4.0741 52.2481
21.0000 4.2473 53.4501
22.0000 4.4107 54.6449
23.0000 4.5648 55.8349
24.0000 4.7101 57.0224
25.0000 4.8472 58.2093
26.0000 4.9763 59.3965
27.0000 5.0976 60.5838
28.0000 5.2115 61.7711
29.0000 5.3176 62.9584
30.0000 5.4166 64.1454
31.0000 5.5087 65.3320
32.0000 5.5940 66.5184
33.0000 5.6729 67.7042
34.0000 5.7454 68.8888
35.0000 5.8118 70.0716
36.0000 5.8728 71.2528
37.0000 5.9309 72.4356
38.0000 5.9885 73.6234
39.0000 6.0480 74.8199
40.0000 6.1113 76.0285
41.0000 6.1808 77.2538
42.0000 6.2588 78.5006
43.0000 6.3481 79.7746
44.0000 6.4519 81.0828
45.0000 6.5747 82.4345
46.0000 6.7226 83.8426
47.0000 6.9046 85.3261
48.0000 7.1327 86.9107
49.0000 7.4175 88.6215
50.0000 7.7720 90.4872
51.0000 8.2112 92.5380
52.0000 8.7520 94.8091
53.0000 9.4079 97.3310
54.0000 10.1726 100.0948
55.0000 10.9956 102.9995
______________________________________
As described above, the present invention can provide a compact and wide ratio zoom lens in the simple focusing method with second lens group which shows excellent imaging property in the entire zoom range and at any photographic distance while minimizing the aberration change.
The manual focus of internal focusing zoom lens with second lens group changing the feed amount for focusing can be achieved in a very simple arrangement of double structure (fixed barrel and cam barrel), in which the barrel structure is so arranged that during zooming the movement locus of second lens group which is the focusing lens group is formed by a combination of focus cam with compensating zoom cam and the movement loci of first lens group, third lens group and fourth lens group taking no part in focusing are formed by combinations of zoom cams of first lens group, third lens group and fourth lens group, respectively, with the compensating zoom cam.
Claims
1. An internal focusing zoom lens system comprising a first lens group of positive refracting power, a second lens group of negative refracting power, a third lens group of positive refracting power, and a fourth lens group of positive refracting power disposed in the named order from the object side, in which at least said first lens group, said third lens group and said fourth lens group move toward an object during zooming from wide angle to telephoto such that a first air gap increases between said first lens group and said second lens group, a second air gap decreases between said second lens group and said third lens group, and a third air gap decreases between said third lens group and said fourth lens group, and said second lens group is located near to the object side at telephoto end as compared to at wide angle end, and in which said second lens group moves toward the object during focusing and the following conditions are satisfied:
- f.sub.1: a focal length of said first lens group;
- f.sub.2: a focal length of said second lens group;
- .beta..sub.2w: a lateral magnification of said second lens group at wide angle end to infinity;
- f.sub.w: a focal length of the overall system at wide angle end.
2. An internal focusing zoom lens system according to claim 1, which further satisfies the following condition:
- f.sub.3: a focal length of said third lens group;
- f.sub.4: a focal length of said fourth lens group.
3. An internal focusing zoom lens system according to claim 1, which further satisfies the following condition:
- f.sub.3: a focal length of said third lens group;
- f.sub.4: a focal length of said fourth lens group.
4. An internal focusing zoom lens system according to claim 1, wherein if a certain movement locus for zooming is expressed with a variable of rotation angle of a rotation barrel for defining a displacement amount of a lens group along an optical axis, a movement locus of said second lens group which is a focusing lens group is formed by a combination of a focus cam with a compensating zoom cam and movement loci of said first lens group, said third lens group and said fourth lens group which are movable non-focusing lens groups taking no part in focusing are formed by combinations of respective zoom cams corresponding to the first, third and fourth lens groups with said compensating zoom cam.
5. An internal focusing zoom lens system according to claim 2, wherein if a certain movement locus for zooming is expressed with a variable of rotation angle of a rotation barrel for defining a displacement amount of a lens group along an optical axis, a movement locus of said second lens group which is a focusing lens group is formed by a combination of a focus cam with a compensating zoom cam and movement loci of said first lens group, said third lens group and said fourth lens group which are movable non-focusing lens groups taking no part in focusing are formed by combinations of respective zoom cams corresponding to the first, third and fourth lens groups with said compensating zoom cam.
6. An internal focusing zoom lens system according to claim 3, wherein if a certain movement locus for zooming is expressed with a variable of rotation angle of a rotation barrel for defining a displacement amount of a lens group along an optical axis, a movement locus of said second lens group which is a focusing lens group is formed by a combination of a focus cam with a compensating zoom cam and movement loci of said first lens group, said third lens group and said fourth lens group which are movable non-focusing lens groups taking no part in focusing are formed by combinations of respective zoom cams corresponding to the first, third and fourth lens groups with said compensating cam.
7. An internal focusing zoom lens system according to claim 4, wherein shapes of said focus cam, said compensating zoom cam and said zoom cams corresponding to said first, third and fourth lens groups all are nonlinear.
8. An internal focusing zoom lens system according to claim 5, wherein shapes of said focus cam, said compensating zoom cam and said zoom cams corresponding to said first, third and fourth lens groups all are nonlinear.
9. An internal focusing zoom lens system according to claim 6, wherein shapes of said focus cam, said compensating zoom cam and said zoom cams corresponding to said first, third and fourth lens groups all are nonlinear.
10. An internal focusing zoom lens system according to claim 1, which is constructed in accordance with the following lens specifications:
- wherein in the table of specifications, f represents a focal length (mm), FN an F-number, r a radius of curvature of each lens plane (mm), d an interplanar gap between lenses (mm), n and.nu. an index of refraction and an Abbe's number of each lens, L represents a lens disposed in the order from the object side, f&b represent focal distance of the entire system and magnification of the entire system, pos(4) represents closest position at wide angle end, pos(5) represents closest position at the middle position, pos(6) represents closest position at telephoto end;
- wherein accompanying numerals to the characters (r, d, n,.nu., L) represent orders counted from the objective side;
- wherein the middle portion of the table shows values of coefficients defining the shape of an aspherical surface formed on the lens plane r.sub.6 on the object side in the second lens group;
- wherein the aspherical surface is expressed by the following aspherical equation, if a height to the optical axis is h, a distance of a vertex of aspherical surface at h to the tangent plane is x, a conical constant is k, aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order are A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10, respectively, and a paraxial radius of curvature is r: ##EQU2## wherein in the middle portion of the specifications of lens system in the table, there are described in order from the left, values of the conical constant k and the aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order, A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10 and wherein E-n means 10.sup.-n in the values of aspherical coefficients;
- wherein the lower portion in the table shows gaps between lens groups and feed amounts of the second lens group for focusing for each photographic distance of infinity and 850.0 mm at three zooming positions (f=36.0, 60.0, and 103.0 mm) between wide angle end and telephoto end;
- wherein the bottom portion shows focal lengths of the lens groups, a lateral magnification of the second lens group at the wide angle end to infinity, and values corresponding to the conditions of the present invention;
- wherein in the table
- f.sub.1: a focal length of said first lens group;
- f.sub.2: a focal length of said second lens group;
- .beta..sub.2w: a lateral magnification of said second lens group at the wide angle end to infinity;
- f.sub.3: a focal length of said third lens group;
- f.sub.4: a focal length of said fourth lens group.
11. An internal focusing zoom lens system comprising a first lens group of positive refracting power, a second lens group of negative refracting power, a third lens group of positive refracting power, and a fourth lens group of positive refracting power disposed in the named order from the object side:
- in which at least said first lens group, said third lens group and said fourth lens group move toward an object during zooming from wide angle to telephoto such that a first air gap increases between said first lens group and said second lens group, a second air gap decreases between said second lens group and said third lens group, and a third air gap decreases between said third lens group and said fourth lens group, and said second lens group is located near to the object side at telephoto end as compared to at wide angle end;
- in which said first lens group comprises at least one positive lens and at least one negative lens, said second lens group comprises at least one negative lens and at least one positive lens, said third lens group comprises at.least two positive lenses, and said fourth lens group comprises at least one positive lens and at least one negative lens; and
- in which said second lens group moves toward the object during focusing and the following conditions are satisfied:
- f.sub.1: a focal length of said first lens group;
- f.sub.2: a focal length of said second lens group;
- .beta..sub.2w: a lateral magnification of said second lens group at wide angle end to infinity;
- f.sub.w: a focal length of the overall system at wide angle end.
12. An internal focusing zoom lens system according to claim 10, which further satisfies the following condition:
- f.sub.3: a focal length of said third lens group;
- f.sub.4: a focal length of said fourth lens group.
13. An internal focusing zoom lens system according to claim 11, which further satisfies the following condition:
- f.sub.3: a focal length of said third lens group;
- f.sub.4: a focal length of said fourth lens group.
14. An internal focusing zoom lens system according to claim 10, wherein if a certain movement locus for zooming is expressed with a variable of rotation angle of a rotation barrel for defining a displacement amount of a lens group along an optical axis, a movement locus of said second lens group which is a focusing lens group is formed by a combination of a focus cam with a compensating zoom cam and movement loci of said first lens group, said third lens group and said fourth lens group which are movable non-focusing lens groups taking no part in focusing are formed by combinations of respective zoom cams corresponding to the first, third and fourth lens groups with said compensating zoom cam.
15. An internal focusing zoom lens system according to claim 12, wherein if a certain movement locus for zooming is expressed with a variable of rotation angle of a rotation barrel for defining a displacement amount of a lens group along an optical axis, a movement locus of said second lens group which is a focusing lens group is formed by a combination of a focus cam with a compensating zoom cam and movement loci of said first lens group, said third lens group and said fourth lens group which are movable non-focusing lens groups taking no part in focusing are formed by combinations of respective zoom cams corresponding to the first, third and fourth lens groups with said compensating zoom cam.
16. An internal focusing zoom lens system according to claim 13, wherein if a certain movement locus for zooming is expressed with a variable of rotation angle of a rotation barrel for defining a displacement amount of a lens group along an optical axis, a movement locus of said second lens group which is a focusing lens group is formed by a combination of a focus cam with a compensating zoom cam and movement loci of said first lens group, said third lens group and said fourth lens group which are movable non-focusing lens groups taking no part in focusing are formed by combinations of respective zoom cams corresponding to the first, third and fourth lens groups with said compensating zoom cam.
17. An internal focusing zoom lens system according to claim 14, wherein shapes of said focus cam, said compensating zoom cam and said zoom cams corresponding to said first, third and fourth lens groups all are nonlinear.
18. An internal focusing zoom lens system according to claim 15, wherein shapes of said focus cam, said compensating zoom cam and said zoom cams corresponding to said first, third and fourth lens groups all are nonlinear.
19. An internal focusing zoom lens system according to claim 16, wherein shapes of said focus cam, said compensating zoom cam and said zoom cams corresponding to said first, third and fourth lens groups all are nonlinear.
20. An internal focusing zoom lens system having the following lens specifications:
- wherein in the table of specifications, f represents a focal length (mm), FN an F-number, r a radius of curvature of each lens plane (mm), d an interplanar gap between lenses (mm), n and.nu. an index of refraction and an Abbe's number of each lens, L represents a lens disposed in the order from the object side, f&b represent focal distance of the entire system and magnification of the entire system, pos(4) represents closest position at wide angle end, pos(5) represents closest position at the middle position, pos(6) represents closest position at telephoto end;
- wherein accompanying numerals to the characters represent orders counted from the object side;
- wherein the middle portion of the table shows values of coefficients defining the shape of an aspherical surface formed on the lens plane r.sub.6 on the object side in a second lens group and the shape of an aspherical surface formed on the lens plane r.sub.22 on the object side of negative lens L.sub.12 in a fourth lens group;
- wherein the aspherical surface is expressed by the following aspherical equation, if a height to the optical axis is h, a distance of a vertex of aspherical surface at h to the tangent plane is x, a conical constant is k, aspherical Coefficients of second order, fourth order, sixth order, eighth order and tenth order are A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10, respectively, and a paraxial radius of curvature is r: ##EQU3## wherein in the middle portion there are described in order from the left, values of the conical constant k and the aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order, A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10 and wherein E-n means 10.sup.-n in the values of aspherical coefficients;
- wherein the lower portion in the table shows gaps between lens groups and feed amounts for focusing for each photographic distance of infinity and 600.0 mm at three zooming positions (f=28.8, 50.0, and 82.5 mm) between wide angle end and telephoto end;
- wherein the bottom portion shows focal lengths of the lens groups, a lateral magnification of the second lens group at the wide angle end to infinity, and values corresponding to the conditions of the present invention;
- wherein in the table
- f.sub.1: a focal length of a first lens group;
- f.sub.2: a focal length of said second lens group;
- .beta..sub.2w: a lateral magnification of said second lens group at the wide angle end to infinity;
- f.sub.3: a focal length of a third lens group;
- f.sub.4: a focal length of said fourth lens group.
21. An internal focusing zoom lens system having the following lens specifications:
- wherein in the table of specifications, f represents a focal length (mm), FN an F-number, r a radius of curvature of each lens plane (mm), d an interplanar gap between lenses (mm), n and.nu. an index of refraction and an Abbe's number of each lens, L represents a lens disposed in the order from the object side, f&b represent focal distance of the entire system and magnification of the entire system, pos(4) represents closest position at wide angle end, pos(5) represents closest position at the middle position, pos(6) represents closest position at telephoto end;
- wherein accompanying numerals to the characters represent orders counted from the object side;
- wherein the middle portion of the table shows values of coefficients defining the shape of an aspherical surface formed on the lens plane r.sub.6 on the object side in a second lens group;
- wherein the aspherical surface is expressed by the following aspherical equation, if a height to the optical axis is h, a distance of a vertex of aspherical surface at h to the tangent plane is x, a conical constant is k, aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order are A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10, respectively, and a paraxial radius of curvature is r: ##EQU4## wherein in the middle portion there are described in order from the left, values of the conical constant k and the aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order, A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10 and wherein E-n means 10.sup.-n in the values of aspherical coefficients;
- wherein the lower portion in the table shows gaps between lens groups and feed amounts for focusing for each photographic distance of infinity and 800.0 mm at three zooming positions (f=36.0, 70.0, and 131.0 mm) between wide angle end and telephoto end;
- wherein the bottom portion shows focal lengths of the lens groups, a lateral magnification of the second lens group at the wide angle end to infinity, and values corresponding to the conditions of the present invention;
- wherein in the table
- f.sub.1: a focal length of a first lens group;
- f.sub.2: a focal length of said second lens group;
- .beta..sub.2w: a lateral magnification of said second lens group at the wide angle end to infinity;
- f.sub.3: a focal length of a third lens group;
- f.sub.4: a focal length of a fourth lens group.
22. An internal focusing zoom lens system having the following lens specifications:
- wherein in the table of specifications, f represents a focal length (mm), FN an F-number, r a radius of curvature of each lens plane (mm), d an interplanar gap between lenses (mm), n and.nu. an index of refraction and an Abbe's number of each lens, L represents a lens disposed in the order from the object side, f&b represent focal distance of the entire system and magnification of the entire system, pos(4) represents closest position at wide angle end, pos(5) represents closest position at the middle position, pos(6) represents closest position at telephoto end;
- wherein accompanying numerals to the characters represent orders counted from the object side;
- wherein the middle portion of the table shows values of coefficients defining the shape of an aspherical surface formed on the lens plane r.sub.6 on the object side in a second lens group and the shape of an aspherical surface formed on the lens plane r.sub.22 on the object side of negative lens L.sub.12 in a fourth lens group;
- wherein the aspherical surface is expressed by the following aspherical equation, if a height to the optical axis is h, a distance of a vertex of aspherical surface at h to the tangent plane is x, a conical constant is k, aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order are A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10, respectively, and a paraxial radius of curvature is r: ##EQU5## wherein in the middle portion there are described in order from the left values of the conical constant k and the aspherical coefficients of second order, fourth order, sixth order, eighth order and tenth order, A.sub.2, A.sub.4, A.sub.6, A.sub.8 and A.sub.10 and wherein E-n means 10.sup.-n in the values of aspherical coefficients;
- wherein the lower portion of the table shows gaps between lens groups and feed amounts for focusing for each photographic distance of infinity and 800.0 mm at three zooming positions (f=28.8, 50.0, and 103.0 mm) between wide angle end and telephoto end;
- wherein the bottom portion shows focal lengths of the lens groups, a lateral magnification of the second lens group at the wide angle end to infinity, and values corresponding to the conditions of the present invention;
- wherein in the table
- f.sub.1: a focal length of a first lens group;
- f.sub.2: a focal length of said second lens group;
- .beta..sub.2w: a lateral magnification of said second lens group at wide angle end to infinity;
- f.sub.3: a focal length of a third lens group;
- f.sub.4: a focal length of said fourth lens group.
Type: Grant
Filed: Jun 7, 1995
Date of Patent: Dec 16, 1997
Assignee: Nikon Corporation (Tokyo)
Inventors: Kiyotaka Inadome (Kawasaki), Wataru Tatsuno (Yokohama)
Primary Examiner: Scott J. Sugarman
Law Firm: Shapiro and Shapiro
Application Number: 8/481,216
International Classification: G02B 1514;
